Relay device, terminal device, communication control device, and method

ABSTRACT

A mechanism related to a relay node in consideration of movement. The relay device includes: a relay unit that relays a wireless signal between a first device that is a connection destination and one or more subordinate second devices; and a control unit that assigns a network layer IP address, which has a prefix portion that is at least partially common, to each of the one or more second devices.

TECHNICAL FIELD

The present disclosure relates to a relay device, a terminal device, acommunication control device, and a method.

BACKGROUND ART

In a cellular network, a relay device called a relay node has beendesigned. The relay node is located between a base station and a userterminal and has a function of relaying wireless communication. Forexample, a standard related to the relay node in 3GPP has been examinedin the following Non-Patent Literature 1.

CITATION LIST Non-Patent Literature

-   Non-Patent Literature 1: 3GPP TS 36.300 Release 12 V12.8.0 (2016-01)    Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved    Universal Terrestrial Radio Access Network (E-UTRAN); Overall    description; Stage 2

DISCLOSURE OF INVENTION Technical Problem

However, in the above Non-Patent Literature 1, the relay node is assumedto be fixed and a standard in which the relay node is assumed to move isnot described. Therefore, it is desirable to provide a mechanism relatedto a relay node in consideration of movement.

Solution to Problem

According to the present disclosure, there is provided a relay deviceincluding: a relay unit that relays a wireless signal between a firstdevice that is a connection destination and one or more subordinatesecond devices; and a control unit that assigns a network layer IPaddress, which has a prefix portion that is at least partially common,to each of the one or more second devices.

In addition, according to the present disclosure, there is provided aterminal device including: a processing unit that performs communicationwith a relay device by using a first network layer IP address, which isassigned to one or more terminal devices connected to the same relaydevice, and has a prefix portion that is at least partially common.

In addition, according to the present disclosure, there is provided acommunication control device including: a processing unit that notifiesa relay device that relays a wireless signal between a first device thatis a connection destination and one or more subordinate second devicesand assigns a network layer IP address, which has a prefix portion thatis at least partially common, to each of the one or more second devicesof the common portion of the prefix portion.

In addition, according to the present disclosure, there is provided amethod including: relaying a wireless signal between a first device thatis a connection destination and one or more subordinate second devices;and a control unit that assigns a network layer IP address, which has aprefix portion that is at least partially common, to each of the one ormore second devices by a processor.

In addition, according to the present disclosure, there is provided amethod including: performing, by a processor, communication with a relaydevice by using a first network layer IP address, which is assigned toone or more terminal devices connected to the same relay device, and hasa prefix portion that is at least partially common.

In addition, according to the present disclosure, there is provided amethod including: notifying, by a processor, a relay device that relaysa wireless signal between a first device that is a connectiondestination and one or more subordinate second devices and assigns anetwork layer IP address, which has a prefix portion that is at leastpartially common, to each of the one or more second devices of thecommon portion of the prefix portion.

Advantageous Effects of Invention

According to the present disclosure, a mechanism related to a relay nodein consideration of movement is provided as described above. Note thatthe effects described above are not necessarily limitative. With or inthe place of the above effects, there may be achieved any one of theeffects described in this specification or other effects that may begrasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an E-UTRAN architecture that supports a relay node.

FIG. 2 is a diagram illustrating a protocol stack in an S1 user plane.

FIG. 3 is a diagram illustrating a protocol stack in an X2 user plane.

FIG. 4 is a diagram illustrating a protocol stack in an S1 controlplane.

FIG. 5 is a diagram illustrating a protocol stack in an X2 controlplane.

FIG. 6 is a diagram illustrating an example of a schematic configurationof a system according to an embodiment of the present disclosure.

FIG. 7 is a diagram illustrating an example of a protocol stack in a URNaccording to the embodiment.

FIG. 8 is a diagram illustrating an example of a protocol stack incommunication between UE and a server on a PDN through the URN accordingto the embodiment.

FIG. 9 is a block diagram illustrating an example of a configuration ofthe UE according to the embodiment.

FIG. 10 is a block diagram illustrating an example of a configuration ofthe URN according to the embodiment.

FIG. 11 is a block diagram illustrating a configuration of a P-GWaccording to the embodiment.

FIG. 12 is an explanatory diagram of technical features in a firstembodiment.

FIG. 13 is an explanatory diagram of technical features in theembodiment.

FIG. 14 is an explanatory diagram of technical features in theembodiment.

FIG. 15 is an explanatory diagram of technical features in theembodiment.

FIG. 16 is an explanatory diagram of technical features in theembodiment.

FIG. 17 is an explanatory diagram of technical features in theembodiment.

FIG. 18 is an explanatory diagram of technical features in theembodiment.

FIG. 19 is an explanatory diagram of technical features in theembodiment.

FIG. 20 is an explanatory diagram of technical features in theembodiment.

FIG. 21 is an explanatory diagram of technical features in theembodiment.

FIG. 22 is an explanatory diagram of technical features in theembodiment.

FIG. 23 is an explanatory diagram of technical features in theembodiment.

FIG. 24 is an explanatory diagram of technical features in theembodiment.

FIG. 25 is an explanatory diagram of technical features in theembodiment.

FIG. 26 is an explanatory diagram of technical features in theembodiment.

FIG. 27 is an explanatory diagram of technical features in theembodiment.

FIG. 28 is an explanatory diagram of technical features in theembodiment.

FIG. 29 is an explanatory diagram of technical features in theembodiment.

FIG. 30 is an explanatory diagram of technical features in theembodiment.

FIG. 31 is an explanatory diagram of technical features in theembodiment.

FIG. 32 is an explanatory diagram of technical features in theembodiment.

FIG. 33 is an explanatory diagram of technical features in theembodiment.

FIG. 34 is an explanatory diagram of technical features in theembodiment.

FIG. 35 is an explanatory diagram of technical features in theembodiment.

FIG. 36 is an explanatory diagram of technical features in theembodiment.

FIG. 37 is an explanatory diagram of technical features in a secondembodiment.

FIG. 38 is an explanatory diagram of technical features in theembodiment.

FIG. 39 is an explanatory diagram of technical features in theembodiment.

FIG. 40 is an explanatory diagram of technical features in theembodiment.

FIG. 41 is an explanatory diagram of technical features in theembodiment.

FIG. 42 is an explanatory diagram of technical features in theembodiment.

FIG. 43 is an explanatory diagram of technical features in theembodiment.

FIG. 44 is an explanatory diagram of technical features in theembodiment.

FIG. 45 is an explanatory diagram of technical features in theembodiment.

FIG. 46 is a block diagram illustrating an example of a schematicconfiguration of a server.

FIG. 47 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 48 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. Notethat, in this specification and the appended drawings, structuralelements that have substantially the same function and structure aredenoted with the same reference numerals, and repeated explanation ofthese structural elements is omitted.

Further, in this specification and the drawings, there are cases inwhich elements having substantially the same functional configurationare distinguished by adding different letters after the same referencenumeral. For example, a plurality of elements having substantially thesame functional configuration are distinguished as terminal apparatuses100A, 100B, and 100C as necessary. However, when it is not necessary toparticularly distinguish a plurality of elements having substantiallythe same functional configuration, only the same reference numeral isattached. For example, when it is not necessary to particularlydistinguish terminal apparatuses 100A, 100B and 100C, they are referredto simply as a “terminal apparatus 100.”

Note that description will be given in the following order.

1. Introduction

1.1. Relay node

1.2. Technical problems

2. Configuration example

2.1. Configuration example of system

2.2. Configuration example of UE

2.3. Configuration example of URN

2.4. Configuration example of P-GW

3. First Embodiment

3.1. Initial assignment of network layer IP address

3.2. Handling of network layer IP address during handover

3.3. Handling of transport layer IP address during handover

3.4. Effects

4. Second Embodiment

4.1. Introduction

4.2. Flow of Processing

4.3. Effects

5. Use case

6. Application example

7. Conclusion

1. INTRODUCTION

<1.1. Relay Node>>

First, a relay node will be described with reference to FIGS. 1 to 5.

FIG. 1 is an evolved universal terrestrial radio access network(E-UTRAN) architecture that supports a relay node. A relay node (RN) isan entity that relays wireless communication performed by a userterminal (user equipment: UE). A donor eNB (DeNB) is an eNB that isconnected to the relay node. As illustrated in FIG. 1, an S1 interfaceis set between the eNB and MME/S-GW. In addition, the S1 interface andan S11 interface are set between the DeNB and the MME/S-GW. Also, an X2interface is set between the eNB and the DeNB. In addition, the S1interface, the X2 interface, and a Uu interface are set between the DeNBand the relay node (RN).

FIG. 2 is a diagram illustrating a protocol stack in an S1 user plane.FIG. 3 is a diagram illustrating a protocol stack in an X2 user plane.FIG. 4 is a diagram illustrating a protocol stack in an S1 controlplane. FIG. 5 is a diagram illustrating a protocol stack in an X2control plane. Here, all the “IPs” in FIGS. 2 to 5 are IPs in atransport layer. That is, an IP in a network layer has not been assumedfor the relay node.

<1.2. Technical Problems>

(1) Problems

First, since the relay node does not have a network layer IP address, itis difficult to use an IP application when the relay node behaves as aUE.

Second, mobility of the relay node has not been taken intoconsideration. Therefore, although the relay node has a transport layerIP address, transmittivity that accompanies movement related to the IPis not secured. Even if the relay node acquires a network layer IPaddress, a similar problem may occur.

Third, in a case in which a terminal group such as a UE that isconnected to the relay node voluntarily performs an attachment procedure(Attachment Procedure), performs position registration in an MME, andindividually establishes a bearer every time the relay node moves, muchsignaling is needed.

Fourth, if the terminal group moves often, the position registration inthe MME is also performed often, and in accordance with this, muchsignaling is needed. Otherwise, it becomes difficult for the terminalgroup to receive a push application such as paging.

The present disclosure provides an example of a new protocol that solvesthe aforementioned four technical problems.

(2) PRIOR ARTS

As examples of technologies for realizing moving transmittivity of an IPaddress, there are a Mobile IP (RFC3775), a Proxy Mobile IP (RFC5213),and a Network Mobility (RFC3963) defined by the Internet EngineeringTask Force (IETF), for example. However, according to thesetechnologies, it is difficult to secure the IP moving transmittivity ofa user terminal in a case in which a relay node is connected to a relaynode and a mobile network is hierarchically formed, a case in whichhandover is performed between mobile networks, and the like.

In addition, a technology of applying a plurality of IP addresses to arelay node is disclosed in International Publication No. 2012/114527(PCT/JP2011/054401) as an example of the technologies related to theaforementioned technical problems. More specifically, a technology inwhich a DeNB applies a plurality of IP addresses to a subordinate relaynode and an IP address from among the plurality of IP addresses isapplied to another relay node connected to the relay node is disclosed.The aforementioned related arts are technologies that are used whenrelay nodes are connected in series in a row. As described above in thetechnical problems, the prior arts are not related to the IP address tobe applied to the subordinate terminal group of the relay node.

In addition, Table 1 is a table in which existing mobility supportprotocols are summarized. The mobility support protocols can beclassified in terms of two viewpoints. The first viewpoint is aviewpoint regarding which of a (node mobility) protocol that realizesmovement of a node alone and a (network mobility: NEMO) protocol thatrealizes movement of a node group (network) a mobility support protocolis. The second viewpoint is a viewpoint regarding which of a (host-basedglobal mobility) protocol, in which a moving node (or a moving router)relates to signaling for movement management and a moving range is theentire Internet, and a (network-based localized mobility) protocol inwhich a moving node (or a moving router) does not relate to signalingfor movement management and the moving range is only a limited range amobility support protocol is.

A proposed protocol according to the embodiment is a protocol in whichNEMO and a moving node are not related to signaling for movementmanagement and a moving range is only a limited range.

TABLE 1 Node Mobility Network Mobility (NEMO) Host-Based Mobile IPv4[1]NEMO Basic Support Protocol [2] Global Mobility Mobile IPv6[3] NEMOExtensions for MIPv4[4] Network-Based PMIPv6[5] N-PMIPv6[6] LocalizedMobility PMIPv4[7] N-NEMO[8] IPv4 Support P-NEMO[10] for PMIPv6[9]PNEMO[11] PMIPv6-NEMO[12]

Note that the respective protocols in Table 1 are described in detail inthe following documents:

-   [1] C. Perkins. IP Mobility Support for IPv4, Revised,    November 2010. RFC 5944.-   [2] V. Devarapalli, R. Wakikawa, A. Petrescu, and P. Thubert.    Network Mobility (NEMO) Basic Support Protocol, January 2005. RFC    3963.-   [3] C. Perkins, D. Johnson, and J. Arkko. Mobility Support in IPv6,    July 2011. RFC 6275.-   [4] K. Lueng, G Dommety, V. Narayanan, and A. Petrescu. Network    Mobility (NEMO) Extensions for Mobile IPv4, April 2008. RFC 5177.-   [5] S. Gundavelli, K. Lueng, V. Devarapalli, K. Chowdhury, and B.    Patil. Proxy Mobile IPv6, August 2008. RFC 5213.-   [6] I. Soto, C. J. Bernardos, M. Calderon, A. Banchs, and A.    Azcorra. Nemo-Enabled Localized Mobility Support for Internet Access    in Automotive Scenarios. IEEE Communications Magazine, Vol. 47, No.    5, pp. 152-159, 2009.-   [7] K. Lueng, G Dommety, P. Yegani, and K. Chowdhury. WiMAX    Forum/3GPP2 Proxy Mobile IPv4, February 2010. RFC 5563.-   [8] Z. Yan, S. Zhang, H. Zhou, H. Zhang, and I. You. Network    Mobility Support in PMIPv6 Network. In Proceedings of 3rd    International Conference on Ubiquitous and Future Networks    (ICUFN2011), 2011.-   [9] R. Wakikawa and S. Gundavelli. IPv4 Support for Proxy Mobile    IPv6, May 2010. RFC 5844.-   [10] J. H. Lee, T. Ernst, and N. Chilamlurti. Performance Analysis    of PMIPv6-Based NEtwork MObility for Intelligent Transportation    Systems. IEEE Transactions on Vehicular Technology, Vol. 61, No. 1,    January 2012.-   [11] T. Arita and F. Teraoka. PNEMO: A Network-Based Localized    Mobility Management Protocol for Mobile Networks. Journal of    Information Processing, Vol. 20, No. 2, February 2012.-   [12] X. Zhou, J. Korhonen, C. Williams, S. Gundavelli, and CJ.    Bernardos. Prefix Delegation Support for Proxy Mobile IPv6,    March 2014. RFC 7148.

2. CONFIGURATION EXAMPLE

<2.1. Configuration Example of System>

FIG. 6 is a diagram illustrating an example of a schematic configurationof a system according to an embodiment of the present disclosure. Asillustrated in FIG. 6, the system according to the embodiment includesUEs 1, a URN 2, a DeNB 3, an eNB 4, an S-GW 5, a P-GW 6, an MME 7, andan HSS 8. The solid lines connecting the respective parts represent userplanes while the broken lines represent control planes. In addition, UEsrepresent a plurality of UEs 1. The proposed protocol can operate in adomain (network range) of a mobile phone network, for example, asillustrated in FIG. 6. It is a matter of course that the domain may beanother network configuration.

The UE 1 is a terminal device. The user-relay-node (URN) 2 is a relaydevice capable of operating as an UE or an RN. The DeNB 3 is a basestation to which the relay node is connected. The eNB 4 is a basestation. The serving gateway (S-GW) 5 is a gateway that transmits userdata. The P-GW 6 is a gateway that services as a contact point between acore network and an external packet data network (PDN) and is acommunication control device that performs assignment of an IP addressor the like. The mobility management entity (MME) 7 performs movementmanagement of the UE 1, authentication, setting of a transfer route ofuser data, and the like. The home subscriber server (HSS) 8 manages userinformation. In addition, the system according to the embodiment caninclude an entity such as a policy and charging rules function (PCRF)that decides policy control such as QoS and charging control rules,which are applied to the S-GW5 and the P-GW 6.

FIG. 7 is a diagram illustrating an example of a protocol stack in theURN 2 according to the embodiment. As illustrated in FIG. 7, the URN 2has a network layer IP address (that is utilized by an application onthe UE 1 or the URN 2) in addition to an EPC transport layer IP address.

FIG. 8 is a diagram illustrating an example of a protocol stack incommunication between the UE 1 and a server on the PDN through the URN 2according to the embodiment. As illustrated in FIG. 8, the URN 2 isconnected to the DeNB 3 and performs communication with an applicationserver on the PDN through an EPC (the S-GW 5 and the P-GW 6). Inaddition, the URN 2 relays wireless communication between thesubordinate UE 1 and the DeNB 3 that is a connection destination.

<2.2. Configuration Example of UE>

Next, an example of a configuration of the UE 1 according to theembodiment will be described with reference to FIG. 9. FIG. 9 is a blockdiagram illustrating an example of the configuration of the UE 1according to the embodiment. Referring to FIG. 9, the UE 1 includes anantenna unit 110, a wireless communication unit 120, a storage unit 130,and a processing unit 140.

(1) Antenna Unit 110

The antenna unit 110 releases a signal output from the wirelesscommunication unit 120 as electric waves into a space. In addition, theantenna unit 110 converts the electric waves in the space into a signaland outputs the signal to the wireless communication unit 120.

(2) Wireless Communication Unit 120

The wireless communication unit 120 transmits and receives signals. Thewireless communication unit 120 receives a downlink signal from the URN2 or the eNB 4 and transmits an uplink signal to the URN 2 or the eNB 4.

(3) Storage Unit 230

The storage unit 130 temporarily or permanently stores a program andvarious kinds of data for operations of the UE 1.

(4) Processing Unit 140

The processing unit 140 provides various functions of the UE 1. Theprocessing unit 140 includes a communication control unit 141. Note thatthe processing unit 140 can further include components other than thesecomponents. That is, the processing unit 140 can perform operationsother than operations of these components. The communication controlunit 141 has a function of controlling communication with the URN 2.

<2.3. Configuration Example of URN>

Next, an example of a configuration of the URN 2 according to theembodiment will be described with reference to FIG. 10. FIG. 10 is ablock diagram illustrating an example of the configuration of the URN 2according to the embodiment. Referring to FIG. 10, the URN 2 includes anantenna unit 210, a wireless communication unit 220, a storage unit 230,and a processing unit 240.

(1) Antenna Unit 210

The antenna unit 210 releases a signal output from the wirelesscommunication unit 220 as electric waves into a space. In addition, theantenna unit 210 converts the electric waves in the space into a signaland outputs the signal to the wireless communication unit 220.

(2) Wireless Communication Unit 220

The wireless communication unit 220 transmits and receives signals. Forexample, the wireless communication unit 220 receives a downlink signalfrom the DeNB 3 that is a connection destination or the URN 2 that is aconnection destination and transmits an uplink signal to the DeNB 3 thatis a connection destination or the URN 2 that is a connectiondestination. In addition, the wireless communication unit 220 receivesan uplink signal from the UE 1 and transmits a downlink signal to the UE1, for example.

(3) Storage Unit 230

The storage unit 230 temporarily or permanently stores a program andvarious kinds of data for operations of the URN 2.

(4) Processing Unit 240

The processing unit 240 provides various functions of the URN 2. Theprocessing unit 240 includes a relay unit 241 and a communicationcontrol unit 243. Note that the processing unit 240 can further includecomponents other than these components. That is, the processing unit 240can perform operations other than the operations of these components.

The relay unit 241 has a function of relaying a wireless signal betweenthe DeNB 3 (that is, the first device) that is a connection destinationand one or more subordinate UEs 1 or one or more subordinate URNs 2(that is, the second device). The communication control unit 243 has afunction of controlling communication with the UEs 1 and performingconnection processing, handover processing, or the like with the DeNBthat is a connection destination or the URNs 2 that are the connectiondestinations.

<2.4. Configuration Example of P-GW>

Next, an example of a configuration of the P-GW 6 according to theembodiment will be described with reference to FIG. 11. FIG. 11 is ablock diagram illustrating an example of the configuration of the P-GW 6according to the embodiment. Referring to FIG. 11, the P-GW 6 includes anetwork communication unit 610, a storage unit 620, and a processingunit 630.

(1) Network Communication Unit 610

The network communication unit 610 is an interface that performscommunication with other devices. For example, the P-GW 6 performscommunication with other EPC entities in the core network or a serverand the like on the PDN.

(2) Storage Unit 620

The storage unit 620 temporarily or permanently stores a program andvarious kinds of data for operations of the P-GW 6.

(3) Processing Unit 630

The processing unit 630 provides various functions of the P-GW 6. Theprocessing unit 630 includes a communication control unit 631. Note thatthe processing unit 630 can further include components other than thesecomponents. That is, the processing unit 630 can perform operationsother than the operations of these components.

The communication control unit 631 has a function of performing variouskinds of processing related to processing of connection of the UE 1 orthe URN 2 to the network.

3. FIRST EMBODIMENT

<3.1. Initial Assignment of Network Layer IP Address>

Initial assignment of a network layer IP address will be described belowwith reference to FIGS. 12 to 29. In this section, the network layer IPaddress will also be simply referred to as an IP address.

FIG. 12 is an explanatory diagram of initial assignment of the IPaddress. In this section, the initial assignment of the IP address willbe described on the assumption of the network configuration illustratedin FIG. 12. As illustrated in FIG. 12, a UE 1A and a URN 2B areconnected to a URN 2A, a UE 1B and a URN 2C are connected to a URN 2B,and a UE 1C is connected to the URN 2C in this network configuration. Amobile network that each URN 2 forms is also referred to as a movingcell or a virtual cell in the following description. In FIG. 12, thevirtual cell is represented as a rectangle of a broken line. Here, astructure in which another virtual cell is connected to a virtual celllike the virtual cell formed by the URN 2B and the virtual cell formedby the URN 2C is also referred to as a nested structure. In addition,the virtual cell formed by the URN 2B is also referred to as a nestedvirtual cell.

In the frame of 3GPP, an IP address (static IP) registered in advance inthe HSS 8 and an IP address (dynamic IP) secured in advance in the P-GW6 is assigned to the UE 1 in the attachment procedure. In theembodiment, the URN 2 acquires the IP address first through theattachment procedure, and the IP address is then assigned to thesubordinate UE 1.

(1) Assignment of IP Address to URN

If the URN 2 that is also capable of operating as the UE 1 is taken intoconsideration, it is desirable that an IP address also be assigned tothe URN 2. Thus, the URN 2 performs an IP address assignment process toreceive assignment of the IP address and assigns the IP address to theURN 2 itself by transmitting an attachment request message to the MME 7in a manner similar to that in the UE 1.

Note that the S-GW 5 and the P-GW 6 may be realized as function entitiesfor a relay node provided inside the DeNB 3. For example, such aconfiguration can be realized by a virtualization function based onnetwork functions virtualization (NFV).

(1-1) In Case of Static IP

In a case in which an IP address corresponding to identificationinformation (identification: ID) of the URN 2 is registered in the HSS8, the IP address may be included in the attachment acceptance message,and the URN 2 may be notified of the IP address. In that case, aprotocol configuration options (PCO) field defined in a non-accessstratum (NAS) protocol may be utilized as an example of means. FIGS. 13and 14 are diagrams illustrating a PCO format. The IP address isassigned to the URN 2 through such a procedure.

(1-2) In Case of Dynamic IP

An IP address assignment request is transmitted to the MME 7 through anattachment request from the URN 2. However, in a case in which there isno IP address registered in advance in the HSS 8, a request forassigning an IP address to the URN 2 is provided to the P-GW 6.

The P-GW 6 generates an ID (interface identifier (64 bits) in IPv6, forexample) to be applied to the URN 2 that is a request source andnotifies the URN 2 of the ID. This notification may be included in anattachment approval message, for example. In addition, the P-GW 6generates and stores association between a global unique terminal ID(international mobile subscriber identity (IMSI), for example) of theURN 2 and a prefix portion (for example, Prefix/64 of IPv6) of the IPaddress.

For example, the URN 2 may generate a link local address (Link LocalAddress) by using the applied ID (for example, an interface identifierof IPv6), transmit an RS message (Router Advertisement Message) that isa so-called IP protocol to the P-GW 6, and acquire the prefix portion(for example, Prefix/64 of IPv6) of the IP address. For example, theprefix portion of the IP address may be included in the routeradvertisement (RA) message (Router Advertisement Message) transmitted bythe P-GW 6. Then, the URN 2 may generate an IPv6 address by linking theacquired prefix portion to the interface identifier. It is a matter ofcourse that the URN 2 may generate an interface identifier that isdifferent from the interface identifier generated by the P-GW 6 andgenerate the IPv6 address. However, it is preferable that the interfaceidentifier generated here not overlap the interface identifier generatedby the P-GW 6. In addition, the URN 2 may acquire an IP address from aDHCP server by using a DHCPv6 protocol instead of the RS message and theRA message. In this manner, the URN 2 can assign the IP address of theURN 2 itself.

Hereinafter, an example of a specific sequence of processing ofassigning an IP address to the URN 2 will be described with reference toFIG. 15.

FIG. 15 is a sequence diagram illustrating an example of a flow ofprocessing of assigning an IP address to the URN 2 according to theembodiment. The URN 2, the DeNB 3, the S-GW 5, the P-GW 6, the MME 7,the HSS 8, and the PCRF 9 are involved in the sequence.

As illustrated in FIG. 15, the URN 2A transmits an attachment request(Attach Request (PCO IP Address Request)) to the MME 7 first (StepS102). Then, the URN 2A performs identification, authentication,encryption, and the like (Identification/Authentication/Ciphered optionetc.) with the DeNB 3, the MME 7, and the HSS 8 (Step S104). Next, theMME 7 transmits a location request (Location Request) to the HSS 8 (StepS106). Then, the HSS 8 transmits a location request response (LocationRequest Response) to the MME 7 (Step S108). Next, the MME 7 transmits abearer request (Bearer Request) to the S-GW 5 (Step S110). Then, theS-GW 5 performs bearer establishment procedures (Bearer establishmentprocedures) with the PCRF 9 and the P-GW 6 (Step S112). Next, the S-GW 5transmits a bearer request response (Bearer Request Response) to the MME7 (Step S114). Then, the MME 7 transmits attachment acceptance (AttachAccepted) and a radio bearer request (Radio Bearer Request) includingthe interface ID (URN-Interface ID) of the URN 2A to the DeNB 3 (StepS116). Next, the DeNB 3 transmits attachment acceptance (AttachAccepted) and a radio bearer request (Radio Bearer Request) includingthe interface ID (URN-Interface ID) of the URN 2A to the URN 2A (StepS118). In this manner, the URN 2A acquires an interface ID (URNInterface ID) of the URN 2A itself (Step S120). Then, the URN 2Atransmits a radio bearer response (Radio Bearer Response) to the DeNB 3(Step S122). Then, the DeNB 3 transmits the radio bearer response (RadioBearer Response) to the MME 7 (Step S124). Then, the URN 2A transmitsattachment completion (Attach Complete) to the MME 7 (Step S126). Next,the URN 2A can transmit uplink user plane traffic data to the PDN 10 viathe DeNB 3, the S-GW 5, and the P-GW 6 (Step S128). Then, the MME 7transmits a bearer update request (Bearer Update Request) to the S-GW 5(Step S130). Next, the S-GW 5 performs bearer update procedures (Bearerupdate procedures) with the PCRF 9 and the P-GW 6 (Step S132). Then, theS-GW 5 transmits a bearer update response (Bearer Update Response) tothe MME 7 (Step S134). This makes it possible to transmit downlink userplane traffic data from the PDN 10 to the URN 2A via the P-GW 6, theS-GW 5, and the DeNB 3 (Step S136). Then, the URN 2A transmits a routersolicitation (RS) message (Router Solicitation Message) to the P-GW 6(Step S138). Next, the P-GW 6 transmits an RA message (RouterAdvertisement Message) including prefix/64 to the URN 2A (Step S140).Then, the URN 2A generates an IPv6 address (URN IPv6 Address) of the URN2A itself that includes prefix/64 and an interface identifier (StepS142).

(2) Assignment of IP Address to UE

Next, assignment of an IP address to the subordinate UE 1 of the URN 2Awill be described.

The IP address can be assigned to the UE 1 in a manner similar to thatin the URN 2 described above. In the embodiment, in particular, the URN2 assigns an IP address, which has a prefix portion that is at leastpartially common (that is, the same), to each of one or more subordinateUEs 1 or one or more subordinate URNs 2. In this manner, the IPaddresses with the prefix portions that are at least partially commonare assigned to the one or more UEs 1 or URN 2 connected to the same URN2. Then, the subordinate UEs 1 or URNs 2 perform communication with theURN 2 and a higher-order network (P-GW 6 or the like) by using theassigned IP address. The prefix portion may be a subnet prefix in IPv6.For example, the subnet prefix may be 64 higher bits in 128 bits ofIPv6, and 56 higher bits (hereinafter, also described as Prefix/56)among the 64 bits may be the common portion.

For example, the URN 2 utilizes a DHCP-prefix delegation (PD) protocolafter completion of the connection and acquires the prefix portioncommonly assigned to the subordinate UEs 1 from the P-GW 6 or the DHCPserver. Therefore, the P-GW 6 notifies the URN 2 of the common portion(IPv6 Prefix/56) of the prefix portion. The URN 2 may create Prefix/64designating the lower bits of “0000 0000,” for example, as Prefix/56 andassign the IP address when the IP address is assigned to the UE 1 thathas actually sent the connection request. Note that DHCP-PD is describedin detail in “O. Troan and R. Droms. IPv6 Prefix Options for DynamicHost Configuration Protocol (DHCP) version 6, December 2003. RFC 3633.”

For example, the UE 1 generates a link local address (Link LocalAddress) by utilizing the ID (for example, the interface identifier ofthe IPv6) applied in an ordinary procedure. Then, the UE 1 may transmitan RS message that is a so-called IP protocol to the URN 2 and acquirethe prefix portion (Prefix/64) of the IP address generated by the URN 2.For example, Prefix/64 may be included in the RA message. In addition,the UE 1 may acquire the IP address of the UE 1 from the DHCP server byusing the DHCP protocol instead of the RS message and the RA message. Atthat time, the DHCP server can create Prefix/64 by designating the lowerbits of “0000 0000”, for example, for Prefix/56 acquired by the DHCP-PDand notify the UE 1 of Prefix/64 by the URN 2 that is a connectiondestination of the UE 1. At this time, the UE 1 can acquire connectioninformation of the DNS server or the DHCP server and the IP address ofthe URN 2 that is the connection destination by utilizing the PCO or thelike. In this manner, the UE 1 can assign the IP address to the UE 1itself.

Here, a mapping table for generating a bearer on each entity (the P-GW6, the S-GW 5, the DeNB 3, or the like) can be created and stored ineach entity for each bearer tunnel realized on a network. In 3GPP, themapping table is created in response to an instruction from the MME 7.In addition, the MME 7 provides an instruction for updating the bearerfrom a source to a target entity (for example, the DeNB 3 or the S-GW 5)in accordance with movement of the terminal device (for example, the UE1 or the URN 2), and the mapping table is also updated in accordancewith this. In the embodiment, the URN 2 acquires Prefix/56, for example,by using the DHCP-PD for a UE 1 group connected to the URN 2. It isdesirable that information that associates the acquired Prefix/56 withthe acquired URN 2 (for example, identification information (URN_ID) orthe like that the MME 7 creates in a terminal connection process) beadded to the mapping table that the P-GW 6, the S-GW 5, the DeNB 3, orthe like stores. Therefore, the P-GW 6 to which Prefix/56 has beenassigned, for example, may notify the S-GW 5 and the DeNB 3 of theinformation for association. This message is also referred to as routesetup in the following description. Note that the route setup and themapping table will be described later in detail.

Hereinafter, an example of a specific sequence of processing ofassigning an IP address to the UE 1 will be described with reference toFIGS. 16 and 17.

FIGS. 16 and 17 are sequence diagrams each illustrating an example of aflow of processing of assigning an IP address to the UE 1A according tothe embodiment. The UE 1A, URN 2A, the DeNB 3, the S-GW 5, the P-GW 6,the MME 7, the HSS 8, and the PCRF 9 are involved in the sequence.

As illustrated in FIG. 16, it is assumed that the URN 2A has completedthe connection to the network through the aforementioned procedure withreference to FIG. 15, for example, first, and has acquired the IPaddress (Step S202). Then, the URN 2A transmits a DHCP-PD request(DHCP_PD Request) that is for requesting the prefix portion (Prefix/56)of the IP address of the UE 1A to the P-GW 6 (Step S204). Next, the P-GW6 transmits a DHCP-PD response (DHCP_PD Response) including the prefixportion (Prefix/56) of the IP address of the UE 1A to the URN 2A (StepS206). In this manner, the URN 2A acquires the prefix portion(Prefix/56) of the IP address of the UE 1A (Step S208). On the otherhand, the P-GW 6 transmits the route setup (Route Setup) for associatingthe identification information (URN_ID) of the URN 2A with the prefixportion (Prefix/56) to the S-GW 5 (Step S210). The S-GW 5 transfers theroute setup (Route Setup) to the MME 7 (Step S212). The MME 7 transfersthe route setup (Route Setup) to the DeNB 3 (Step S214). Next, the UE 1Atransmits an attachment request (Attach Request (PCO IP Address Request)to the MME 7 (Step S216). Then, the UE 1A performs identification,authentication, encryption (Identification/Authentication/Cipheredoption etc.) with the URN 2A, the DeNB 3, the MME 7, and the HSS 8 (StepS218). Next, the MME 7 transmits a location request (Location Request)to the HSS 8 (Step S220). Then, the HSS 8 transmits a location requestresponse (Location Request Response) to the MME 7 (Step S222).

Next, the MME 7 transmits a bearer request (Bearer Request) to the S-GW5 as illustrated in FIG. 17 (Step S224). Then, the S-GW 5 performsbearer establishment procedures (Bearer establishment procedures) withthe PCRF 9 and the P-GW 6 (Step S226). Then, the S-GW 5 transmits abearer request response (Bearer Request Response) to the MME 7 (StepS228). Then, the MME 7 transmits an attachment acceptance (AttachAccepted) and radio bearer request (Radio Bearer Request) including theinterface ID (UE-Interface ID) of the UE 1A to the DeNB 3 (Step S230).Next, the DeNB 3 transmits an attachment acceptance (Attach Accepted)and a radio bearer request (Radio Bearer Request) including theinterface ID (UE-Interface ID) of the UE 1A to the URN 2A (Step S232).Then, the URN 2A transmits an attachment acceptance (Attach Accepted)and a radio bearer request including an interface ID (UE-Interface ID)of the UE 1A to the UE 1A (Step S234). In this manner, the UE 1Aacquires the interface identifier (UE interface ID) of the UE 1A itself(Step S236). Next, the UE 1A transmits a radio bearer response (RadioBearer Response) to the URN 2A (Step S238). Then, the URN 2A transmits aradio bearer response (Radio Bearer Response) to the DeNB 3 (Step S240).Next, the DeNB 3 transmits a radio bearer response (Radio BearerResponse) to the MME 7 (Step S242). Then, the UE 1A transmits attachmentcompletion (Attach Complete) to the MME 7 (Step S244). Next, the UE 1Acan transmit uplink user plane traffic data to the PDN 10 via the URN2A, the DeNB 3, the S-GW 5, and the P-GW 6 (Step S246). Then, the MME 7transmits a bearer update request (Bearer Update Request) to the S-GW 5(Step S248). Next, the S-GW 5 performs bearer update procedures (Bearerupdate procedures) with the PCRF 9 and the P-GW 6 (Step S250). Then, theS-GW 5 transmits a bearer update response (Bearer Update Response) tothe MME 7 (Step S252). This makes it possible to transmit downlink userplane traffic data from the PDN 10 to the UE 1A via the P-GW 6, the S-GW5, the DeNB 3, and the URN 2A (Step S254). Then, the UE 1A transmits anRS message (Router Solicitation Message) to the URN 2A (Step S256).Next, the URN 2A transmits an RA message (Router Advertisement Message)including Prefix/64 to the UE 1A (Step S258). Then, the UE 1A generatesan IPv6 address (UE IPv6 Address) of the UE 1A itself includingPrefix/64 and the interface identifier (Step S260).

(3) Assignment of IP Address Related to URN with Nested Structure

Next, assignment of an IP address related to the URN 2 with the nestedstructure will be described.

Hereinafter, an example of a specific sequence of processing ofassigning an IP address related to the URN with the nested structurewill be described with reference to FIGS. 18 to 21. Here, an example ofa flow of processing of assigning IP addresses to the URN 2B connectedto the URN 2A and the UE 1B connected to the URN 2B will be described asan example.

FIGS. 18 to 21 are sequence diagrams illustrating an example of a flowof processing of assigning IP addresses to the URN 2B connected to theURN 2A and the UE 1B connected to the URN 2B according to theembodiment. The UE 1B, the URN 2B, the URN 2A, the DeNB 3, the S-GW 5,the P-GW 6, the MME 7, the HSS 8, and the PCRF 9 are involved in thesequence.

As illustrated in FIG. 18, it is assumed that the URN 2A has completedthe connection to the network through the aforementioned procedure withreference to FIG. 15, for example, first, and has acquired the IPaddress (Step S302). Then, the URN 2A transmits a DHCP-PD request(DHCP_PD Request) that is for requesting the prefix portion (Prefix/56)of the IP address of the URN 2B to the P-GW 6 (Step S304). Next, theP-GW 6 transmits a DHCP-PD response (DHCP_PD Response) including theprefix portion (Prefix/56) of the IP address of the URN 2B to the URN 2A(Step S306). In this manner, the URN 2A acquires the prefix portion(Prefix/56) of the IP address of the URN 2B (Step S308). On the otherhand, the P-GW 6 transmits the route setup (Route Setup) for associatingthe identification information (URN_ID) of the URN 2B with the prefixportion (Prefix/56) to the S-GW 5 (Step S310). The S-GW 5 transfers theroute setup (Route Setup) to the MME 7 (Step S312). The MME 7 transfersthe route setup (Route Setup) to the DeNB 3 (Step S314). Next, the URN2B transmits an attachment request (Attach Request (PCO IP AddressRequest) to the MME 7 (Step S316). Then, the URN 2B performsidentification, authentication, encryption(Identification/Authentication/Ciphered option etc.) with the URN 2A,the DeNB 3, the MME 7, and the HSS 8 (Step S318). Next, the MME 7transmits a location request (Location Request) to the HSS 8 (StepS320). Then, the HSS 8 transmits a location request response (LocationRequest Response) to the MME 7 (Step S322).

Next, the MME 7 transmits a bearer request (Bearer Request) to the S-GW5 as illustrated in FIG. 19 (Step S324). Then, the S-GW 5 performsbearer establishment procedures (Bearer establishment procedures) withthe PCRF 9 and the P-GW 6 (Step S326). Then, the S-GW 5 transmits abearer request response (Bearer Request Response) to the MME 7 (StepS328). Then, the MME 7 transmits an attachment acceptance (AttachAccepted) and radio bearer request (Radio Bearer Request) including theinterface ID (URN Interface ID) of the URN 2B to the DeNB 3 (Step S330).Next, the DeNB 3 transmits an attachment acceptance (Attach Accepted)and a radio bearer request (Radio Bearer Request) including theinterface ID (URN Interface ID) of the URN 2B to the URN 2A (Step S332).Then, the URN 2A transmits an attachment acceptance (Attach Accepted)and a radio bearer request including an interface ID (URN Interface ID)of the URN 2B to the URN 2B (Step S334). In this manner, the URN 2Bacquires the interface identifier (UE interface ID) of the URN 2B itself(Step S336). Next, the URN 2B transmits a radio bearer response (RadioBearer Response) to the URN 2A (Step S338). Then, the URN 2A transmits aradio bearer response (Radio Bearer Response) to the DeNB 3 (Step S340).Next, the DeNB 3 transmits a radio bearer response (Radio BearerResponse) to the MME 7 (Step S342). Then, the URN 2B transmitsattachment completion (Attach Complete) to the MME 7 (Step S344). Next,the URN 2B can transmit uplink user plane traffic data to the PDN 10 viathe URN 2A, the DeNB 3, the S-GW 5, and the P-GW 6 (Step S346). Then,the MME 7 transmits a bearer update request (Bearer Update Request) tothe S-GW 5 (Step S348). Next, the S-GW 5 performs bearer updateprocedures (Bearer update procedures) with the PCRF 9 and the P-GW 6(Step S350). Then, the S-GW 5 transmits a bearer update response (BearerUpdate Response) to the MME 7 (Step S352). This makes it possible totransmit downlink user plane traffic data from the PDN 10 to the URN 2Bvia the P-GW 6, the S-GW 5, the DeNB 3, and the URN 2A (Step S354).

Then, the URN 2B transmits an RS message (Router Solicitation Message)to the URN 2A as illustrated in FIG. 20 (Step S356). Next, the URN 2Atransmits an RA message (Router Advertisement Message) includingPrefix/64 to the URN 2B (Step S358). Then, the URN 2B generates an IPv6address (URN IPv6 Address) of the URN 2B itself that includes Prefix/64and the interface identifier (Step S360).

The processing of assigning the IP address to the URN 2B connected tothe URN 2A has been described above. Next, processing of assigning an IPaddress to the UE 1B connected to the URN 2B will be described.

First, the UE 1B transmits an attachment request (Attach Request (PCO IPAddress Request) to the MME 7 (Step S402). Then, the UE 1B performsidentification, authentication, encryption(Identification/Authentication/Ciphered option etc.) with the URN 2B,the URN 2A, the DeNB 3, the MME 7, and the HSS 8 (Step S404). Next, theMME 7 transmits a location request (Location Request) to the HSS 8 (StepS406). Then, the HSS 8 transmits a location request response (LocationRequest Response) to the MME 7 (Step S408).

Next, the MME 7 transmits a bearer request (Bearer Request) to the S-GW5 as illustrated in FIG. 17 (Step S410). Then, the S-GW 5 performsbearer establishment procedures (Bearer establishment procedures) withthe PCRF 9 and the P-GW 6 (Step S412). Then, the S-GW 5 transmits abearer request response (Bearer Request Response) to the MME 7 (StepS414). Then, the MME 7 transmits an attachment acceptance (AttachAccepted) and radio bearer request (Radio Bearer Request) including theinterface ID (UE-Interface ID) of the UE 1A to the DeNB 3 (Step S416).Next, the DeNB 3 transmits an attachment acceptance (Attach Accepted)and a radio bearer request (Radio Bearer Request) including theinterface ID (UE-Interface ID) of the UE 1A to the URN 2A (Step S418).Then, the URN 2A transmits an attachment acceptance (Attach Accepted)and a radio bearer request including an interface ID (UE-Interface ID)of the UE 1B to the URN 2B (Step S420). Next, the URN 2B transmits anattachment acceptance (Attach Accepted) and a radio bearer requestincluding an interface ID (UE-Interface ID) of the UE 1B to the UE 1B(Step S422). In this manner, the UE 1A acquires the interface identifier(UE interface ID) of the UE 1A itself (Step S424). Then, the UE 1Btransmits a radio bearer response (Radio Bearer Response) to the URN 2B(Step S426). Next, the URN 2B transmits a radio bearer response (RadioBearer Response) to the URN 2A (Step S428). Then, the URN 2A transmits aradio bearer response (Radio Bearer Response) to the DeNB 3 (Step S430).Next, the DeNB 3 transmits a radio bearer response (Radio BearerResponse) to the MME 7 (Step S432). In this manner, the UE 1B transmitsattachment completion (Attach Complete) to the MME 7 (Step S434). Next,the UE 1A can transmit uplink user plane traffic data to the PDN 10 viathe URN 2B, the URN 2A, the DeNB 3, the S-GW 5, and the P-GW 6 (StepS436). Then, the MME 7 transmits a bearer update request (Bearer UpdateRequest) to the S-GW 5 (Step S438). Next, the S-GW 5 performs bearerupdate procedures (Bearer update procedures) with the PCRF 9 and theP-GW 6 (Step S440). Then, the S-GW 5 transmits a bearer update response(Bearer Update Response) to the MME 7 (Step S442). This makes itpossible to transmit downlink user plane traffic data from the PDN 10 tothe UE 1B via the P-GW 6, the S-GW 5, the DeNB 3, the URN 2A, and theURN 2B (Step S444). Then, the UE 1B transmits an RS message (RouterSolicitation Message) to the URN 2A (Step S446). Next, the URN 2Atransmits an RA message (Router Advertisement Message) includingPrefix/64 to the UE 1A (Step S448). Then, the UE 1B generates an IPv6address (UE IPv6 Address) of the UE 1A itself including Prefix/64 andthe interface identifier (Step S450).

Here, the prefix portion may be hierarchized to correspond to thenetwork with the nested structure. The hierarchization of the prefixportion will be described with reference to FIGS. 22 and 23.

FIG. 22 is an explanatory diagram of hierarchization of the prefixportion of the IPv6 according to the embodiment. As illustrated in FIG.22, the IP address of the IPv6 is 128 bits. The higher bits among themare also referred to as a prefix portion, and the remaining lower bitsare also referred to an interface identifier. Although the respectivelengths are arbitrary, both the lengths are assumed to be 64 bits inthis specification. In addition, each of the plurality of virtual cellsformed by the URN 2 or another URN 2 may be identified by the non-commonportion of the prefix portion of the IP address of 64 bits. For example,a higher portion 101 (56 bits in the example illustrated in FIG. 22) isa region that is prefix-delegated by the highest URN 2. In addition, amiddle portion 102 (2 bits in the example illustrated in FIG. 22) is aregion for identifying a virtual network. Note that the virtual networkis a network with a nested structure including the plurality of virtualcells. In addition, a lower portion 103 (6 bits in the exampleillustrated in FIG. 22) is a region for identifying a virtual cell ineach virtual network. It is possible to express the network with thenested structure illustrated in FIG. 23, for example, by suchhierarchization.

FIG. 23 is a diagram illustrating an example of the network with thenested structure. As illustrated in FIG. 23, a plurality of virtualnetworks are connected to the DeNB 3. The virtual network “0” is a groupof virtual cells, in which a URN 2A-0 is the highest. The virtualnetwork “1” is a group of virtual cells, in which a URN 2A-1 is thehighest. The virtual network “3” is a group of virtual cells, in which aURN 2A-3 is the highest. These respective virtual networks areidentified by the middle portion 102.

The plurality of virtual cells are included in the virtual network.Hereinafter, description will be given by focusing on the virtualnetwork “0”. A virtual cell formed by the URN 2B-01 and a virtual cellformed by the URN 2B-02 are connected to the virtual cell formed by theURN 2A-0. These virtual cells can also be referred to as one-stagenested virtual cells. In addition, a virtual cell formed by the URN 2C-0is connected to the virtual cell formed by the URN 2B-02. This virtualcell can also be referred to as two-stage nested virtual cell. Althoughnot illustrated in the drawing, there may be a three-stage or morenested virtual cell. These virtual cells included in a single virtualnetwork are identified by the lower portion 103. Similar description isapplied to other virtual networks.

Since the individual virtual cells are uniquely identified by suchhierarchization of the prefix portion of the IP address, it is possibleto simplify the mapping table (routing table), which will be describedlater. Further, it becomes unnecessary to update the mapping table in ahigher order when the cell or the terminal located in a lower ordermoves.

In order to realize such hierarchization, the rectangular portion “A” ofthe broken line is replaced with the sequence illustrated in FIG. 24,and the rectangular portion “C” is replaced with the sequenceillustrated in FIG. 25 from among the sequences illustrated in FIGS. 18to 21. FIGS. 24 and 25 are sequence diagrams illustrating an example ofa flow of processing of assigning IP addresses to the URN 2B connectedto the URN 2A and the UE 1B connected to the URN 2B according to theembodiment.

As illustrated in FIG. 24, the URN 2B transmits a DHCP_PD request(DHCP_PD Request) that is for requesting the prefix portion (Prefix/60)of the IP address of the URN 2B itself to the URN 2A (Step S356A). Next,the URN 2A transmits a DHCP-PD response (DHCP_PD Response) including theprefix portion (Prefix/60) of the IP address of the URN 2B to the URN 2B(Step S358A). Then, the URN 2B designates the lower bits “0000”, forexample, for the acquired prefix portion (Prefix/60) to createsPrefix/64 and generates a IPv6 address (URN IPv6 Address) of the URN 2Bitself that includes Prefix/64 and the interface identification (StepS360A).

The URN 2B hierarchizes the subordinate URN 2C and the like by using thelower 4 bits of the prefix portion (Prefix/60) of the IP addressacquired in Step S358A. For example, the URN 2B assigns different lower4 bits for each subordinate virtual cell, and in a case in which aDHCP_PD request message is received from the subordinate URN 2C or thelike, the URN 2B replies the prefix portion (Prefix/64), to which thelower 4 bits have been assigned, in a DHCP_PD response message.Therefore, the UE 1 receives designation of the prefix portion(Prefix/64) of the IP address from the connected URN 2 rather than theURN 2 in the highest order in the virtual network. A sequence in thiscase is as illustrated in FIG. 25.

Then, the UE 1B transmits an RS message (Router Solicitation Message) tothe URN 2B as illustrated in FIG. 25 (Step S446A). Next, the URN 2Btransmits an RA message (Router Advertisement Message) including layeredPrefix/64 to the UE 1B (Step S448A). Then, the UE 1B generates an IPv6address (UE IPv6 Address) of the UE 1B itself that includes Prefix/64and the interface identifier (Step S450A).

Here, bears are set from the UE 1 to the P-GW 6 through the URN 2, theDeNB 3, and the S-GW 5 as illustrated in FIG. 26. FIG. 26 is an exampleillustrating examples of the bears and traffic flow templates (TFTs) setfrom the UE 1 to the P-GW 6.

A transmission path set between the URN 2 and the P-GW 6 may be divertedfor the section between the URN 2 and the P-GW 6 in the transmissionpath set between the subordinate UE 1 or the subordinate URN 2 and theP-GW 6. Note that the transmission path described here may be a bearer,or in a case in which a bearerless network, the transmission path may bean IP flow. In regard to the sequence described in FIGS. 18 to 21, thebearer from the P-GW 6 to the URN 2A established by the rectangle ‘B-1”of the broken line may be diverted for the bearer from the P-GW 6 to theUE 1B established by the rectangle ‘B-2” of the broken line. In thismanner, bearers of the group of UEs 1 connected to the URN 2, that is,the group of UEs 1 that have IP addresses with common prefix portionscan be aggregated, and it becomes possible to significantly reduce theamount of signaling that accompanies establishment of the bearers.Hereinafter, such a bearer configuration of a virtual cell will bedescribed with reference to FIG. 27.

FIG. 27 is a diagram illustrating an example of a bearer configurationof a virtual cell. As illustrated in FIG. 27, a default bearer and adedicated bearer (dedicated) are respectively established between theURN 2 and the UE 1. Meanwhile, the individual bearer and the dedicatedbearer are not established for each UE 1 between the UE 1 and the P-GW6. Instead, the default bearer and the dedicated bearer establishedbetween the URN 2 and the UE 1 are mapped to the dedicated bearerestablished between the URN 2 and the P-GW 6. In this manner, the UE 1can utilize the dedicated bearer that the URN 2 that is the connectiondestination has established with the P-GW 6 without individuallyestablishing the bearers from the URN 2 to the P-GW 6.

Here, one dedicate bearer established between the URN 2 and the P-GW 6may be diverted (that is, shared) by a plurality of subordinate UE 1 ormay be individually diverted by one UE 1. For example, each of thedefault bearer of the group of the UEs 1 and the dedicated bearer of“Policy-1” is mapped to one dedicated bearer established between the URN2 and the P-GW 6. Meanwhile, each of default bearers “#1” and “# m” inthe group of UEs 1 are mapped to different dedicated bearers establishedbetween the URN 2 and the P-GW 6.

The URN 2 individually utilizes the default bearer of the URN 2 itself.The URN 2 may establish and secure a plurality of dedicated bearer foreach band or each policy such as QoS, for example, for the subordinateUE 1 or the subordinate URN 2.

It is a matter of course that the UE 1 may establish a bearer with theP-GW 6 without diverting the bearer established between the URN 2 andthe P-GW 6.

Description will be given with reference to the aforementioned sequence.When the bearer between the URN 2 and the P-GW 6 is established in therectangular portion “A” of the broken line in the sequence illustratedin FIG. 15, for example, the URN 2 establishes and secures a pluralityof dedicated bearers in advance for the UE 1 that will be connected tothe URN 2 in the future. Then, when the UE 1 establishes the bearer inthe rectangular portion “A” of the broken line in the sequenceillustrated in FIGS. 16 and 17, only a radio bearer between the UE 1 andthe URN 2 is newly established, and a bearer established and secured inadvance is utilized as the bearer from the URN 2 to the P-GW 6. Theradio bearer newly established corresponds to the thick broken lineportion in Step S246 and Step S254 in FIG. 17. Similar description isalso applied to the sequence in FIGS. 18 to 21.

It is a matter of course that the proposed protocol can also be appliedto an architecture in a next-generation network that is not compatiblewith EPC of existing 3GPP. Such an architecture will be described withreference to FIGS. 28 and 29.

FIGS. 28 and 29 are diagrams illustrating an example of an architectureof a next-generation network. FIG. 28 illustrates an architecture of abearerless network that is realized by a so-called pure IP network. Inthis case, an IP flow is in charge of a role of the bearer. In thisarchitecture, it is possible to realize IP transmittivity of the groupof UEs 1 connected to the URN 2 without the mechanism such as a mobileIP, by commonly setting the prefix portions. FIG. 29 illustrates anarchitecture in which a control plane and a user plane are separated byutilizing a cloud.

<3.2. Handling of Network Layer IP Address During Handover>

Hereinafter, handling of a network layer IP address during handover thataccompanies movement of the UE 1 or the URN 2 will be described withreference to FIGS. 30 to 36. In this section, the network layer IPaddress will also simply be referred to as an IP address.

FIG. 30 is an explanatory diagram of handling of the IP address duringhandover. In this section, handling of the IP address during handoverthat accompanies transition of the network configuration illustrated inFIG. 30 will be described. As illustrated in FIG. 30, the UE 1 isinitially connected to the eNB 4. The handover represented by thereference numeral 111 is handover of the UE 1. The handover representedby the reference numerals 112 to 114 is handover of the URN 2A. Here, ahandover procedure of a relay node is not clearly defined in the 3GPP.

(1) Handover Represented by Reference Numeral 111

The UE 1 performs handover from the eNB 4 to the URN 2A. The UE 1 hasalready acquired the IP address through the attachment procedureperformed at the time of connection to the eNB 4. Therefore, the UE 1continuously utilizes an IP address acquired before the handover evenafter the handover in accordance with the framework of the handoveraccording to the 3GPP. Therefore, the UE 1 utilizes an IP address thatis different from the IP address which is assigned to the UE that isinitially connected to the virtual cell of the URN 2A and has a commonprefix portion (Prefix/56) after the handover. Note that an EPS bearerup to the P-GW 6 is updated by the attachment procedure.

In a case in which the UE 1 has already acquired the IP address, hascompleted the attachment procedure, and has generated the IP addressincluding the prefix portion of the virtual cell after handover, the UE1 stores a clock time at which the procedure for attachment to the URN2A has been completed. Then, the UE 1 uses the IP address (that is, afirst network layer IP address) newly assigned after the handover to asocket that is opened after the stored clock time at which the procedurefor attachment to the URN 2A has been completed. On the other hand, theUE 1 continuously uses the IP address (that is, a second network layerIP address) assigned before the handover to a socket that is openedbefore the stored clock time at which the attachment to the URN 2 hasbeen completed. Therefore, if the socket that is opened before thestored clock time is closed, this means that use of the IP addressacquired before the handover has ended. In this manner, it becomespossible for the UE 1 to utilize the new IP address with elapse of timeafter the handover and to benefic advantages such as sharing of bearersand utilization of mapping tables, which will be described later. The UE1 may notify the URN 2A to which the UE 1 is being connected ofinformation indicating that the socket using the IP address assignedbefore the handover has been closed, that is, information indicatingthat the utilization of the IP address assigned before the handover hasended. In this manner, it becomes possible to save the amount ofinformation in the mapping tables, which will be described later, andhierarchization and the like of routing in the virtual cell is realized.

In addition, the UE 1 utilizes a bearer established and secured by theURN 2A located in the highest order in the virtual cell for the group ofUEs 1 in the virtual cell in advance through the attachment procedurewhen the UE 1 utilizes the new IP address. Basically, update of thebearer is performed by the MME 7 through the attachment procedure, andan EPS bearer dedicated for each UE 1 and each URN 2 is established.Each bearer is mapped with a tunnel endpoint identifier (TEID) of ageneral packet radio service (GPRS) tunneling protocol (GTP) and a radiobearer ID and is established. Here, mapping tables managed by the P-GW6, the S-GW 5, the DeNB 3, and the URN 2 will be described later indetail.

(2) Handover Represented by Reference Numeral 112

The URN 2A performs handover from a DeNB 3A to a DeNB 3B. This handoveris handover that utilizes a logical path (X2 interface) between theDeNBs 3 without switching of the S-GW 5. Here, the URN 2A behaves as theUE 1, and handover between base stations from the DeNB 3A to the DeNB 3Bis performed.

The URN 2A continuously utilizes the IP address, which has been assignedbefore the handover, even after the handover in accordance with theframe of handover in 3GPP. In accordance with this, the group ofsubordinate UEs 1 of the URN 2A also continuously utilizes the IPaddresses, which have been assigned before the handover, even after thehandover of the URN 2A.

Here, the URN 2 may notify the group of subordinate UEs 1 of informationindicating that the URN 2 itself will start handover (or is attemptingto perform handover) (Step S514 in FIG. 31, for example). In addition,the URN 2 may notify the group of subordinate UEs 1 of informationindicating that the URN 2 itself has completed the handover (Step S544in FIG. 32, for example). In this manner, the subordinate devices canprevent shifting to handover to another URN 2 during the handover of theURN 2A. For example, if the UE 1 is notified of the information that theURN 2A that is a connection destination performs handover, the UE 1 mayactivate a handover timer or the like and prevent the procedure forattachment to another network for a predetermined period of time afterthe URN 2 starts the handover. In this manner, it becomes possible tosuppress unnecessary signaling required for the handover procedure. Itis not necessary for the group of the UEs 1 in the virtual cell toindividually attempt the attachment procedure after the completion ofthe handover.

Hereinafter, an example of a flow of processing in the aforementionedhand over represented by the reference numeral 112 will be describedwith reference to FIGS. 31 and 32.

FIGS. 31 and 32 are sequence diagrams illustrating an example of a flowof handover processing performed by the URN 2 according to theembodiment. The group of UEs 1, the URN 2A, the DeNB 3A, the DeNB 3B,the MME 7, the S-GW 5, and the P-GW 6 are involved in the sequence. Inaddition, the group of UEs 1 and the URN 2A form a virtual cell. Inaddition, the DeNB 3A is a source DeNB while the DeNB 3B is a targetDeNB.

As illustrated in FIG. 31, the group of UEs 1, the URN 2A, the DeNB 3A,the S-GW 5A, and the P-GW 6 are in a state in which they transmit andreceive uplink and downlink user plane traffic data first (Step S502).Then, the URN 2A transmits a measurement report (RCC-URN: MeasurementReport) to the DeNB 3A (Step S504). Next, the DeNB 3A performs handoverdetermination (Handover Decision) (Step S506). Then, the DeNB 3Atransmits a handover request (X2-AP: Handover Request) to the DeNB 3B(Step S508). Next, the DeNB 3B transmits a handover request ACK (X2-AP:Handover Request Ack) to the DeNB 3A (Step S510). Then, the DeNB 3Atransmits a handover command (RCC-URN: Handover Command) to the URN 2A(Step S512). Next, the URN 2A transmits a handover notification(RCC-UEs: Handover Notification) to the group of subordinate UEs 1 (StepS514). In this manner, the group of UEs 1 starts the handover timer,holds the state (UEs State Hold/HO-Timer Start), and suppresses handoverto another URN 2 (Step S516). Then, the DeNB 3A transfers data(Forwarding of data) to the DeNB 3B for executing handover (HandoverExecution) (Step S518).

Next, the DeNB 3B transmits downlink data (Downlink data) to the URN 2Afor completing handover (Handover Completion) as illustrated in FIG. 32(Step S520). This makes it possible for the URN 2A to transmit uplinkuser plane traffic data to the P-GW 6 via the DeNB 3B and the S-GW 5A(Step S522). Next, the DeNB 3B transmits a path switch request (PathSwitch Request) to the MME 7 (Step S524). Then, the MME 7 transmits abearer modification request (Modify Bearer Request) to the S-GW 5A (StepS526). Next, the S-GW 5A performs bearer modification procedures (ModifyBearer procedures) with the P-GW 6 (Step S528). Then, the S-GW 5Atransmits a bearer modification response (Modify Bearer Response) to theMME 7 (Step S530). This makes it possible for the P-GW 6 to transmitdownlink user plane traffic data to the URN 2A via the S-GW 5A and theDeNB 3B (Step S532). Then, the S-GW 5A transmits an end marker (EndMarker) to the DeNB 3A (Step S534). Next, the DeNB 3A transmits the endmarker (End Marker) to the DeNB 3B (Step S536). Then, the MME 7transmits a path switch request ACK (Path Switch Request Ack) to theDeNB 3B (Step S538). Next, the DeNB 3B transmits a release resource(Release Resource) to the DeNB 3A (Step S540). Then, the URN 2A performsupdate procedures (Tracking/Address/etc. Update procedures) of tracking,addresses, and the like between the DeNB 3B and the MME 7 (Step S542).Next, the URN 2A transmits handover completion (RCC-UEs: HandoverCompletion) to the group of subordinate UEs 1 (Step S544). In thismanner, the group of UEs 1 stops the handover timer and opens the state(UEs State Release/HO-Timer Stop (Step S546). Then, the group of UEs 1,the URN 2A, the DeNB 3B, the S-GW 5A, and the P-GW 6 transmit andreceive uplink and downlink user plane traffic data (Step S548).

(10) Handover Represented by Reference Numeral 113

The URN 2A performs handover from the DeNB 3A to the URN 2B. Thehandover described here can be performed by a procedure that is similarto that for the handover represented by the reference numeral 112described above with reference to FIGS. 31 and 32.

For example, the URN 2A continuously utilizes the IP address, which hasbeen assigned before the handover, even after the handover in accordancewith the frame of handover in 3GPP. In accordance with this, the groupof subordinate UEs 1 of the URN 2A also continuously utilizes the IPaddresses, which have been assigned before the handover, even after thehandover of the URN 2A.

For example, the URN 2A may notify the group of subordinate UEs 1 of areport that the URN 2A is attempting to perform handover and that thehandover has been completed. Operations of the group of subordinate UEs1 are also as described above.

(4) Handover Represented by Reference Numeral 114

The URN 2A performs handover from the URN 2B to a DeNB 3C. The handoveris handover that utilizes a logical path (X2 Interface) between DeNBs 3including a change from the S-GW 5A to the S-GW 5B. Here, the URN 2Abehaves as the UE 1, and handover between base stations from the URN 2Bto the DeNB 3C is performed. Basically, the URN 2B is regarded as asource DeNB, the DeNB 3C is regarded as a target DeNB, and the mechanismof 3GPP is applied. That is, the handover described herein can also beperformed by a procedure that is similar to that for the respectivehandover described above.

For example, the URN 2A continuously utilizes the IP address, which hasbeen assigned before the handover, even after the handover in accordancewith the frame of handover in 3GPP. In accordance with this, the groupof subordinate UEs 1 of the URN 2A also continuously utilizes the IPaddresses, which have been assigned before the handover, even after thehandover of the URN 2A.

For example, the URN 2A may notify the group of subordinate UEs 1 of areport that the URN 2A is attempting to perform handover and that thehandover has been completed. Operations of the group of subordinate UEs1 are also as described above.

Hereinafter, an example of a flow of processing in the aforementionedhand over represented by the reference numeral 113 will be describedwith reference to FIGS. 33 and 34.

FIGS. 33 and 34 are sequence diagrams illustrating an example of a flowof handover processing performed by the URN 2 according to theembodiment. The group of UEs 1, the URN 2A, the URN 2B, the DeNB 3C, theMME 7, the S-GW 5A, the S-GW 5B, and the P-GW 6 are involved in thesequence. In addition, the group of UEs 1 and the URN 2A form a virtualcell. In addition, the URN 2B is a source DeNB while the DeNB 3C is atarget DeNB. In addition, the S-GW 5A is a source S-GW while the S-GW 5Bis a target S-GW.

As illustrated in FIG. 33, the group of UEs 1, the URN 2A, the URN 2B,the S-GW 5A, and the P-GW 6 are in an initial state in which they cantransmit and receive uplink and downlink user plane traffic data first(Step S602). Then, the URN 2A transmits a measurement report (RCC-URN:Measurement Report) to the URN 2B (Step S604). Next, the URN 2B performshandover determination (Handover Decision) (Step S606). Then, the URN 2Btransmits a handover request (X2-AP: Handover Request) to the DeNB 3C(Step S608). Next, the DeNB 3C transmits a handover request ACK (X2-AP:Handover Request Ack) to the URN 2B (Step S610). Then, the URN 2Btransmits a handover command (RCC-URN: Handover Command) to the URN 2A(Step S612). Next, the URN 2A transmits a handover notification(RCC-UEs: Handover Notification) to the group of subordinate UEs 1 (StepS614). In this manner, the group of UEs 1 starts the handover timer,holds the state (UEs State Hold/HO-Timer Start), and suppresses handoverto another URN 2 (Step S616). Then, the URN 2B transfers data(Forwarding of data) to the DeNB 3C for executing handover (HandoverExecution) (Step S618).

Next, the DeNB 3C transmits downlink data (Downlink data) to the URN 2Afor completing handover (Handover Completion) as illustrated in FIG. 34(Step S620). This makes it possible for the URN 2A to transmit uplinkuser plane traffic data to the P-GW 6 via the DeNB 3C and the S-GW 5A(Step S622). Next, the DeNB 3C transmits a path switch request (PathSwitch Request) to the MME 7 (Step S624). Then, the MME 7 transmits asession creation request (Create Session Request) to the S-GW 5B (StepS626). Next, the S-GW 5B performs bearer modification procedures (ModifyBearer procedures) with the P-GW 6 (Step S628). Then, the S-GW 5Btransmits a session creation response (Create Session Response) to theMME 7 (Step S630). Next, the P-GW 6 transmits downlink user planetraffic data to the URN 2A via the S-GW 5B and the DeNB 3C (Step S632).Then, the MME 7 transmits path switch request ACK (Path Switch RequestAck) to the DeNB 3C (Step S634). Next, the URN 2A transmits uplink userplane traffic data to the P-GW 6 via the DeNB 3C and the S-GW 5B (StepS636). Then, the DeNB 3C transmits a release resource (Release Resource)to the URN 2B (Step S638). Next, the MME 7 transmits a session deletionrequest (Delete Session Request) to the S-GW 5A (S640). Then, the S-GW5A transmits a session deletion response (Delete Session Response) tothe MME 7 (S642). Next, the URN 2A performs update procedures(Tracking/Address/etc. Update procedures) of tracking, addresses, andthe like between the DeNB 3C and the MME 7 (Step S644). Next, the URN 2Atransmits handover completion (RCC-UEs: Handover Completion) to thegroup of subordinate UEs 1 (Step S646). In this manner, the group of UEs1 stops the handover timer and opens the state (UEs StateRelease/HO-Timer Stop) (Step S648). This makes it possible for the groupof UEs 1, the URN 2A, the DeNB 3C, the S-GW 5B, and the P-GW 6 totransmit and receive uplink and downlink user plane traffic data (StepS650).

Although the handover procedure utilizing the X2 interface has beendescribed above, it is a matter of course that a handover procedureutilizing an S1 interface may be performed. Processing in a case inwhich the handover represented by the reference numeral 114 is performedby utilizing the S1 interface will be described as one example withreference to FIGS. 35 and 36.

FIGS. 35 and 36 are sequence diagrams illustrating an example of a flowof handover processing performed by the URN 2 according to theembodiment. The group of UEs 1, the URN 2A, the URN 2B, the DeNB 3C, theMME 7A, the MME 7B, the S-GW 5A, the S-GW 5B, and the P-GW 6 areinvolved in the sequence. In addition, the group of UEs 1 and the URN 2Aform a virtual cell. In addition, the URN 2B is a source DeNB while theDeNB 3C is a target DeNB. In addition, the S-GW 5A is a source S-GWwhile the S-GW 5B is a target S-GW. In addition, the MME 7A is a sourceMME while the MME 7B is a target MME.

As illustrated in FIG. 35, the group of UEs 1, the URN 2A, the URN 2B,the S-GW 5A, and the P-GW 6 are brought into an initial state in whichthey can transmit and receive uplink and downlink user plane trafficdata first (Step S702). Then, the URN 2A transmits a measurement report(RCC-URN: Measurement Report) to the URN 2B (Step S704). Then, the URN2B performs handover determination (Handover Decision via S1) utilizingthe S1 interface (Step S706). Then, the URN 2B transmits a handoverrequest (S1-AP: Handover required) to the MME 7A (Step S708). Next, theMME 7A transmits a forward relocation request (Forward RelocationRequest) to the MME 7B (Step S710). Then, the MME 7B transmits a sessioncreation request (Create Session Request) to the S-GW 5B (Step S712).Next, the S-GW 5B transmits a session creation response (Create SessionResponse) to the MME 7B (Step S714). Then, the MME 7B transmits ahandover request (Handover Request) to the DeNB 3C (Step S716). Next,the DeNB 3C transmits a handover request ACK (Handover Request Ack) tothe MME 7B (Step S718). Then, the MME 7B transmits an indirect datatransfer tunnel creation request (Create Indirect Data Forwarding TunnelRequest) to the S-GW 5B (Step S720). Next, the S-GW 5B transmits anindirect data transfer tunnel creation response (Create Indirect DataForwarding Tunnel Response) to the MME 7B (Step S722). Then, the MME 7Btransmits a forward relocation response (Forward Relocation Response) tothe MME 7A (Step S724). Next, the MME 7A transmits an indirect datatransfer tunnel creation request (Create Indirect Data Forwarding TunnelRequest) to the S-GW 5A (Step S726). Then, the S-GW 5A transmits anindirect data transfer tunnel creation response (Create Indirect DataForwarding Tunnel Response) to the MME 7A (Step S728). Next, the MME 7Atransmits a handover command (Handover Command) to the URN 2B (StepS730). Then, the URN 2B transmits the handover command (RCC-URN:Handover command) to the URN 2A (Step S732). Next, the URN 2A transmitsa handover notification (RCC-UEs: Handover Notification) to the group ofsubordinate UEs 1 (Step S734). In this manner, the group of UEs 1 startsthe handover timer, holds the state (UEs State Hold/HO-Timer Start), andsuppresses handover to another URN 2 (Step S736). Then, the URN 2Btransmits a base station status transfer (eNB Status Transfer) to theMME 7A (Step S738). Next, the MME 7A transmits a forward access contextnotification (Forward Access Context Notification) to the MME 7B (StepS740). Then, the MME 7B transmits a forward access context approval(Forward Access Context Acknowledge) to the MME 7A (Step S742). Next,the MME 7B transmits a base station status transfer (eNB StatusTransfer) to the DeNB 3C (Step S744). Then, the URN 2B transmits onlydirect transfer data (Only for Direct forwarding of data) to the DeNB 3C(Step S746). Next, the URN 2B transmits indirect transfer data (Only forIndirect forwarding of data) to the DeNB 3C via the S-GW 5A and the S-GW5B in a case of indirect transfer data (Step S748).

Then, the URN 2A performs detachment from the old cell andsynchronization with the new cell (Detach from old cell andsynchronization to new cell) with the URN 2B, the DeNB 3C, the MME 7A,and the MME 7B as illustrated in FIG. 36 (Step S750). Next, the URN 2Atransmits handover confirmation (Handover Confirm) to the DeNB 3C (StepS752). Then, the DeNB 3C transmits downlink data (Downlink data) to theURN 2A (Step S754). This makes it possible for the URN 2A to transmituplink user plane traffic data to the P-GW 6 via the DeNB 3 c and theS-GW 5B (Step S756). Then, the DeNB 3C transmits a handover notification(Handover Notify) to the MME 7B (Step S758). Next, the MME 7B transmitsa forward relocation completion notification (Forward RelocationComplete Notification) to the MME 7A (Step S760). Then, the MME 7Atransmits a forward relocation completion conformation (ForwardRelocation Complete Acknowledge) to the MME 7B (Step S762). Next, theMME 7B transmits a bearer modification request (Modify Bearer Request)to the S-GW 5B (Step s764). Then, the S-GW 5B performs bearermodification procedures (Modify Bearer procedures) with the P-GW 6 (StepS766). Next, the S-GW 5B transmits a bearer modification response(Modify Bearer Response) to the MME 7B (Step S768). This makes itpossible for the P-GW 6 to transmit downlink user plane traffic data tothe URN 2A via the S-GW 5B and the DeNB 3C (Step S770). Next, the URN 2Aperforms update procedures (Tracking/Address/etc. Update Procedures) oftracking, addresses, and the like with the URN 2B, the DeNB 3C, the MME7A, and the MME 7B (Step S772). Then, the URN 2A transmits handovercompletion (RCC-UEs: Handover Completion) to the group of subordinateUEs 1 (Step S774). In This manner, the group of UEs 1 stops the handovertimer and opens the state (UEs State Release/HO-Timer Stop) (Step S776).Next, the MME 7A transmits a URN context release command (URN ContextRelease Command) to the URN 2B (Step S778). Then, the URN 2B transmitsURN context release completion (URN Context Release Complete) to the MME7A (Step S780). Next, the MME 7A transmits a session deletion request(Delete Session Request) to the S-GW 5A (Step S782). Then, the S-GW 5Atransmits a session deletion response (Delete Session Response) to theMME 7A (Step S784). Next, the MME 7A transmits an indirect data transfertunnel deletion request (Delete Indirect Data forwarding Tunnel Request)to the S-GW 5A (Step S786). Then, the S-GW 5A transmits an indirect datatransfer tunnel deletion response (Delete Indirect Data forwardingTunnel Response) to the MME 7A (Step S788). Next, the MME 7B transmitsan indirect data transfer tunnel deletion request (Delete Indirect Dataforwarding Tunnel Request) to the S-GW 5B (Step S790). Then, the S-GW 5Btransmits an indirect data transfer tunnel deletion response (DeleteIndirect Data forwarding Tunnel Response) to the MME 7B (Step S792).This makes it possible to transmit and receive uplink and downlink userplane traffic data via the group of UEs 1, the URN 2A, the DeNB 3C, theS-GW 5B, and the P-GW 6 (Step S794).

<3.3. Handling of Transport Layer IP Address During Handover>

Hereinafter, handling of a transport layer IP address during handoverthat accompanies movement of the UE 1 or the URN 2 will be described.

As illustrated in FIG. 8, an EPC transport layer IP address isordinarily applied to a network device. However, mobility of the networkis not taken into consideration in 3GPP. If a case in which the URN 2behaves as the UE 1 is assumed, it is difficult to assign the transportlayer IP address to the URN 2 in advance in some cases. Thus, amechanism in which a transport layer IP address is automaticallyassigned at the time of network connection, such as a so-calledautomatic configuration (Auto Configuration) can be considered. If theautomatic configuration and mobility of the URN 2 are taken intoconsideration as described above, it is assumed that the transport layerIP address is changed whenever the URN 2 moves.

For example, the URN 2 sets an ID (an e NB ID or the like assigned tothe IMSI or the URN 2, for example) for specifying the URN 2 itself asan IPv6 interface identifier when the URN 2 connects to a network. Inaddition, the URN 2 acquire Prefix/64 through an RS message and an RAmessage exchanged with the DeNB 3 that is a connection destination byusing the IPv6 link local address. Then, the URN 2 may generate thetransport layer IP address of the URN 2 itself by combining the set IPv6interface identifier with Prefix/64.

The URN 2 may continuously utilize the thus generated transport layer IPaddress even after the handover. In addition, the URN 2 may generate anew transport layer IP address by the similar method every time handoveris performed. The handover described herein can mean that the DeNB 3that is a connection destination changes or that the URN 2 that is aconnection destination changes.

In any cases, the MME 7 updates management information related to thetransport layer IP address of the URN 2 when the URN 2 performsRCC/S1-AP/NAS communication with the MME 7 (for example, updateprocedures (Tracking/Address/etc. Update procedures) of tracking,addresses, and the like in FIGS. 32, 34, and 36, for example). Note thatStep S806 in FIG. 38 and Step S1106 in FIG. 41, which will be describedlater, are examples of the aforementioned automatic configuration.

<3.4. Effects>

Hereinafter, main effects of the aforementioned protocol will bedescribed.

For example, a network layer IP address is assigned to the URN 2.Therefore, IP moving transmittivity is realized. In addition, the URN 2can utilize the IP application in a manner similar to that in the UE 1.Further, D2D communication using network layer IP addresses between theUE1 and the UE 1, between the UE 1 and the URN 2, or between the URN 2and the URN 2 is easily realized.

In addition, the automatic configuration with the EPC transport layer IPaddress is realized. This makes it possible to dynamically assign thetransport layer IP address to the URN 2 that an end user utilizes everytime the URN 2 connects to the network or every time handover isperformed. Therefore, in a manner similar to that in a stationary RN, itis possible to perform network maintenance, bearer establishment by theMME 7, and the like in a manner similar to that in other EPC deviceseven in a case in which the URN 2 moves.

In addition, the UEs 1 connected to the URN 2 can omit performing theconnection processing again even in a case in which the URN 2 performshandover. Therefore, the UEs 1 can perform reception of paging,utilization of a push application, and the like without updatingposition registration (Tracking Area Update) and the like. In thismanner, it becomes possible to significantly reduce the amount ofsignaling (for example, a tracking area update message) from thesubordinate UEs 1 of the URN 2. In this manner, reduction of signalingmessages, which accompany movement, from a group of wearable devicesconnected to a virtual cell or the UEs 1 connected to a virtual cellformed in a moving vehicle is realized.

In addition, the URN 2 can take the UEs 1 and the URN 2 that haveaddresses other than ones with common Prefix/56 utilized in thesubordinate virtual cells into the virtual cell. Accordingly, it ispossible to taken terminals, which have already been connected to thenetwork, into the virtual cell.

4. SECOND EMBODIMENT

In the embodiment, the first embodiment will be described in detail interms of generation and update of mapping tables.

<4.1. Introduction>

FIG. 37 is a diagram illustrating a network configuration exampleaccording to the embodiment. Hereinafter, the embodiment will bedescribed on the assumption of the network configuration exampleillustrated in FIG. 37. As illustrated in FIG. 37, the system includesvirtual cells that are formed by a P-GW 6, an S-GW 5A, an S-GW 5B, anMME 7, a DeNB 3A, a DeNB 3B, and URN 2A. A UE 1A and a UE 1B, a URN 2Bthat forms a nested virtual cell to which a UE 1C is connected, a URN 2Cthat forms a nested virtual cell to which a UE 1D is connected, and aURN 2D that forms a nested virtual cell to which a UE 1E is connectedcan be connected to the virtual cell formed by the URN 2A.

An IPv6 address of an interface on a downstream side of the P-GW will berepresented as IP^(D) _(PGW). An IPv6 address of an interface on anupstream or downstream side of the S-GW will be represented as IP^(U)_(SGW) or IP^(D) _(SGW), respectively. An IPv6 address of an interfaceon an upstream or downstream side of the DeNB will be represented asIP^(U) _(DeNB) or IP^(D) _(DeNB). An IPv6 address for the URN 2 tooperate as an eNB and to be connected to a DeNB on the upstream sidewith an S1-U interface will be referred to as IP^(U) _(URN). An IPv6address, which is for the URN 2 to operate as a UE and is used by anapplication on the URN, will be represented as IP^(UE) _(URN). An IPv6address, which is for the URN 2 to operate as a moving router and isused for communicating with a device in a virtual cell on the downstreamside will be represented as IP^(D) _(URN).

<4.2. Flow of Processing>

(1) Procedure for Connection of URN 2A which has not Yet Acquired IPv6Address to DeNB 3A>

Hereinafter, a flow of processing performed when the URN 2A, which hasnot yet acquired an IPv6 address, is connected to the DeNB 3A andacquires the IPv6 address will be described with reference to FIG. 38.For example, the processing can be executed in a case in which a powersource of the URN 2A is turned on in the vicinity of the DeNB 3A.

FIG. 38 is a sequence diagram illustrating an example of a flow ofprocessing of connecting the URN 2A to the DeNB 3A according to theembodiment. The URN 2A, the DeNB 3A, the MME 7, the S-GW 5A, and theP-GW 6 are involved in the sequence.

As illustrated in FIG. 38, the URN 2A establishes a wireless line withthe DeNB 3A first (Step S802).

Then, the URN 2A transmits router solicitation (RS) directed to a linklocal all-router multiple-cast address (Step S804). The source addressof the RS is a link local IPv6 address of the URN 2A.

Next, the DeNB 3A receives the RS and transmits router advertisement(RA) directed to the link local IPv6 address of the URN 2A (Step S806).The RA includes higher 64 bits (prefix) of IP^(D) _(DeNB3A).

Then, the URN 2A receives the RA and generates an IPv6 address IP^(U)_(URN2A) (Step S808). The IP^(U) _(URN2A) is used when the URN 2Aestablishes a GTP tunnel with the DeNB 3A.

Next, the URN 2A transmits an attachment request to the DeNB 3A (StepS810). The attachment request includes an identifier ID_(URN2A) andIP^(U) _(URN2A) of the URN 2A.

Then, the DeNB 3A receives the attachment request and transfers theattachment request to the MME 7 (Step S812).

Next, the MME 7 transmits a default bearer creation request (CreateDefault Bearer Request) to the S-GW 5A (Step S814). The default bearercreation request includes ID_(URN2A) and IP^(U) _(URN2A).

Then, the S-GW 5A receives the default bearer creation request andtransfers the default bearer creation request to the P-GW 6 (Step S816).

Next, the P-GW 6 receives the default bearer creation request andassigns the IPv6 address IP^(UE) _(URN2A) from an IPv6 address spacethat the P-GW 6 itself has (Step S818). IP^(UE) _(URN2A) is an IPv6address that is used by the application when the URN 2A operates as aUE. The P-GW 6 forms a GTP tunnel with the S-GW 5A and associates atransfer destination of IP^(UE) _(URN2A) with the GTP tunnel. Theassociation is stored in a mapping table. End points of the GTP tunnelare IP^(D) _(PGW6) and IP^(U) _(SGW5A).

Then, the P-GW 6 transmits a default bearer creation response (CreateDefault Bearer Response) to the S-GW 5A (Step S820). The default bearercreation response (Create Default Bearer Response) includes ID_(URN2A),IP^(UE) _(URN2A), and IP^(DP) _(PGW6).

Next, the S-GW 5A receives the default bearer creation response andtransfers the default bearer creation response to the MME 7 (Step S822).The S-GW 5A forms a GTP tunnel with the P-GW 6. End points of the GTPtunnel are IP^(U) _(SGW5A) and IP^(D) _(PGW6). Further, the S-GW 5Aforms a GTP tunnel with the DeNB 3A and associates IP^(UE) _(URN2A) withthe GTP tunnel. The association is stored in a mapping table. End pointsof the GTP tunnel are IP^(D) _(SGW5A) and IP^(U) _(DeNB3A).

Then, the MME 7 receives the default bearer creation response andtransmits attachment acceptance to the DeNB 3A (Step S824). Theattachment acceptance includes ID_(URN2A), lower 64 bits (if-id:interface identification) of IP^(UE) _(URN2A), and IP^(D) _(PGW6).

Next, the DeNB 3A receives the attachment acceptance and transfers theattachment acceptance to the URN 2A (Step S826). The DeNB 3A forms a GTPtunnel with the S-GW 5A. End points of the GTP tunnel are IP^(U)_(DeNB3A) and IP^(D) _(SGW5A). Further, the DeNB 3A forms a GTP tunnelwith the URN 2A and associates a transfer destination of IP^(UE)_(URN2A) with the GTP tunnel. The association is stored in a mappingtable. End points of the GTP tunnel are IP^(D) _(DeNB3A) and IP^(U)_(URN2A). The URN 2A receives the attachment acceptance and obtainslower 64 bits (if-id) of IP^(UE) _(URN2A).

As a result of the aforementioned signaling, the GTP tunnels aregenerated between the P-GW 6 and the S-GW 5A, between the S-GW 5A andthe DeNB 3A, and between the DeNB 3A and the URN 2A (Step S828).

Then, the URN 2A transmits RS to the P-GW 6 in accordance withprovisions of the IPv6 in order to obtain the IPv6 address IP^(UE)_(URN2A) for operating as a UE (Step S830).

Next, the P-GW 6 receives the RS and replies RA to the URN 2A (StepS832). The RA includes higher 64 bits (prefix) of IP^(UE) _(URN2A).

Then, the URN 2A receives the RA and obtains higher 64 BITS (prefix) ofIP^(UE) _(URN2A). Then, the URN 2A generates IP^(UE) _(URN2A) (StepS834). IP^(UE) _(URN2A) is used when an application above the URN 2Aperforms communication.

Next, the URN 2A executes DHCP-PD (Prefix Delegation) with the P-GW 6(Step S836).

As a result of the DHCP-PD, the URN 2A obtains prefix Pref_(URN2A) (anIPv6 address space of /60, for example) of the IPv6 address (Step S838).The P-GW 6 associates the transfer destination of Pref_(URN2A) with theGTP tunnel to the S-GW 5A. The association is stored in a mapping table.Meanwhile, the URN 2A selects the IPv6 address IP^(D) _(URN2A) from thespace of Pref_(URN2A). IP^(D) _(URN2A) is assigned to an interface onthe downstream side of the URN 2A.

Then, the P-GW 6 transmits a route setup message to the S-GW 5A (StepS840). The router setup message is information for associating theprefix Pref_(URN2A) of the IPv6 address with the URN 2A, and devices(for example, the S-GW 5A, the DeNB 3A, and the like) that relaycommunication between the URN 2A and the P-GW 6 is notified of theinformation. Specifically, the route setup message includes informationindicating that the transfer destination of Pref_(URN2A) is to beassociated with IP^(UE) _(URN2A).

Next, the S-GW 5A receives the route setup message and associates thetransfer destination of Pref_(URN2A) with IP^(UE) _(URN2A) (Step S842).Then, the S-GW 5A relays the route setup message to the MME 7.

Then, the MME 7 receives the route setup message and transfers the routesetup message to the DeNB 3A (Step S844). The DeNB 3A receives the routesetup message and associates the transfer destination of Pref_(URN2A)with IP^(UE) _(URN2A).

As a result, the P-GW 6, the S-GW 5A, and the DeNB 3A store the mappingtables illustrated in Tables 2, 3, and 4, respectively.

TABLE 2 (Mapping table stored in P-GW 6) End point IPv6 address Transferdestination Route URN IP^(UE) _(URN2A) GTP_(SGW5A) — Pref_(URN2A) SeeIP^(UE) _(URN2A) ID_(URN2A)

TABLE 3 (Mapping table stored in S-GW 5A) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(DeNB3A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A)

TABLE 4 (Mapping table stored in DeNB 3A) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(URN2A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A)

The above mapping tables will be described. For example, according tothe entry on the first row in Table 2, a packet directed to IP^(UE)_(URN2A) is transferred to “GTP_(SGW5A)” (that is, the GTP tunneldirected to the S-GW 5A) described in the transfer section of the entrywith the end point IPv6 address of IP^(UE) _(URN2A). In this manner, thepacket is transferred to the S-GW 5A. Then, according to the entry onthe first row in Table 3, the packet directed to IP^(UE) _(URN2A) istransferred to “GTP_(DeNB3A)” (that is, the GTP tunnel directed to theDeNB 3A) described in the transfer section of the entry with the endpoint IPv6 address of IP^(UE) _(URN2A). In this manner, the packet istransferred to the DeNB 3A. Then, according to the entry on the firstrow in Table 4, the packet directed to IP^(UE) _(URN2A) is transferredto “GTP_(URN2A)” (that is, the GTP tunnel directed to the URN 2A)described in the transfer section of the entry with the end point IPv6address of IP^(UE) _(URN2A). In this manner, the packet is transferredto the URN 2A. In this manner, each entity can appropriately transferthe packet and cause the packet to reach the destination by referring tothe stored mapping table.

In addition, according to the entry on the second row in Table 2, thepacket with the destination IP address with the prefix portion ofPref_(URN2A) is transferred to “GTP_(SGW5A)” that is the transferdestination of the entry on the first row with the end point IPv6address of IP^(UE) _(URN2A) on the basis of “See IP^(UE) _(URN2A)”described in the transfer section. In this manner, the packet istransferred to the S-GW 5A. In addition, according to the entry on thesecond row in Table 3, the packet with the destination IP address withthe prefix portion of Pref_(URN2A) is transferred to “GTP_(DeNB3A)” thatis a transfer destination of the entry on the first row with the endpoint IPv6 address of IP^(UE) _(URN2A) on the basis of “See IP^(UE)_(URN2A)” described in the transfer section. In this manner, the packetis transferred to the DeNB 3A. In addition, according to the entry onthe second row in Table 4, the packet with the destination IP addresswith the prefix portion of Pref_(URN2A) is transferred to “GTP_(URN2A)”that is a transfer destination of the entry on the first row with theend point IPv6 address of IP^(UE) _(URN2A) on the basis of “See IP^(UE)_(URN2A)” described in the transfer section. In this manner, the packetis transferred to the URN 2A. Each entity can appropriately transfer thepacket and cause the packet to reach the destination with reference tothe stored mapping table.

In this manner, the respective entities (the P-GW 6, the S-GW 5, theDeNB 3, and the like) store the prefix portion assigned to the terminal(the UE 1 or the URN 2) connected to the URN 2 in association with theURN 2. The respective entities can transmit packets directed to thesubordinate terminals of the URN 2 to the URN 2 and finally cause thepackets to reach the respective terminals with reference to theassociation.

(2) Procedure for Connection of UE1A which has not Yet Acquired IPv6Address to URN 2A

Hereinafter, a flow of processing performed in a case in which the UE 1Athat has not yet acquired the IPv6 address is connected to the URN 2A toacquire the IPv6 address after the aforementioned connection processingwill be described. The processing can be executed in a case in which thepower source of the UE 1A is turned on in the vicinity of the URN 2A,for example.

FIG. 39 is a sequence diagram illustrating an example of a flow ofprocessing of connecting the UE 1A to the URN 2A according to theembodiment. The UE 1A, the URN 2A, the DeNB 3A, the MME 7, the S-GW 5A,and the P-GW 6 are involved in the sequence.

As illustrated in FIG. 39, the UE 1A establishes a wireless line withthe URN 2A first (Step S902).

Then, the UE 1A transmits an attachment request to the URN 2A. Theattachment request includes an identifier ID_(UE1A) of the UE 1A (StepS904).

Next, the URN 2A transmits an attachment acceptance to the UE 1A (STEPs906). The attachment acceptance includes lower 64 bits (if-id) for theUE 1A to form IP_(UE1A) and IP^(D) _(URN2A). The UE 1A receives theattachment acceptance and obtains the lower 64 bits of IP_(UE1A).

Then, the UE 1A transmits RS to the URN 2A (Step S908).

Next, the URN 2A receives the RS and transmits RA including the higher64 bits (prefix) of IP^(D) _(URN2A) to the UE1A (Step S910).

Then, the UE 1A receives the RA and generates IP_(UE1A) (Step S912).

Thereafter, the URN 2A waits for a time to some extent (for example, 1second) and collectively transmit attachment requests related to the UEs1 connected on the downstream side of the URN 2A during the time to theDeNB 3A (Step S914). That is, the URN 2A can avoid transmittance of anattachment request every time each UE 1 is connected to the downstreamof the URN 2A, by transmitting the attachment requests related to theplurality of UEs 1 at a time. Each attachment request includes anidentifier (for example, ID_(UE1A)) and an IPv6 address (for example,IP_(UE1A)) of the UE 1A connected to the URN 2A and informationindicating that the connection is UE connection to the virtual cell.

Next, the DeNB 3A receives the attachment requests and transfers theattachment requests to the MME 7 (Step S916).

Then, the MME 7 receives the attachment requests and transmitsattachment acceptance to the DeNB 3A (Step S918).

Next, the DeNB 3A receives the attachment accept and transfers theattachment acceptance to the URN 2A (Step S920).

As a result of the above processing, there is no change in the mappingtable stored in each of the P-GW 6, the S-GW 5A, and the DeNB 3A. Thatis, the amount of information stored in the P-GW 6, the S-GW 5A, and theDeNB 3A does not depend on the number of UEs 1 with power sources thathave been turned on in the virtual cell provided by the URN 2.

(3) Procedure for Connection of UE 1B which has Already Acquired IPv6Address to URN 2A

Hereinafter, a flow of processing performed in a case in which the UE 1Bthat has already acquired the IPv6 address is connected to the URN 2Aafter the aforementioned connection processing will be described. Forexample, it is assumed that the UE 1B has obtained the IPv6 addressIP_(UE1B) before the connection to the URN 2A. What is to be noted hereis that IP_(UE1B) does not belong to Pref_(URN2A). For example, theprocessing can be executed in a case in which the UE 1B that has beenconnected to anther eNB 4 is connected to the virtual cell that the URN2A provides.

FIG. 40 is a sequence diagram illustrating an example of a flow ofprocessing of connecting the UE 1B to the URN 2A according to theembodiment. The UE 1B, the URN 2A, the DeNB 3A, the MME 7, the S-GW 5A,and the P-GW 6 are involved in the sequence.

As illustrated in FIG. 40, the UE 1B establishes a wireless line withthe URN 2A first (Step S1002).

Then, the UE 1B transmits an attachment request to the URN 2A (StepS1004). The attachment request includes the identifier ID_(UE1B) andIP_(UE1B) of the UE 1B.

Next, the URN 2A transmits attachment acceptance including the lower 64bits (if-id) of IP_(UE1B) to the UE 1B (Step S1006).

Then, the URN 2A generates an IPv6 address IP^(D2) _(URN2A) and assignsthe IPv6 address to the interface on the downstream side (Step S1008).At that time, the URN 2A sets the higher 64 bits (prefix) of IP^(D2)_(URN2A) to be equal to the higher 64 bits (prefix) of IP_(UE1B).

Next, the UE 1B transmits RS to the URN 2A in accordance with provisionsof the IPv6 (Step S1010).

Then, the URN 2A receives the RS and transmits RA including the higher64 bits (prefix) of IP_(UE1B) and the higher 64 bits (prefix) of IP^(D)_(URN2A) to the UE 1B (Step S1012).

Next, the UE 1B receives the RA and checks that IP_(UE1B) is available(Step S1014). In addition, the UE 1B uses the higher 64 bits (prefix) ofIP^(D) _(URN2A) and generates an IPv6 address IP^(URN2A) _(UE1B).IP_(UE1B) does not belong to Pref_(URN2A) while IP^(URN2A) _(UE1B)belongs to Pref_(URN2A). The application that has performedcommunication before the UE 1B connects to the URN 2A continuously usesIP_(UE1B), and the application that has started communication after theUE 1B connects to the URN 2A uses IP^(URN2A) _(UE1B) In this manner,IP_(UE1B) is not used in the course of time. The fact that IP_(UE1B) hasnot been used by the UE 1B can be detected by the following method. Forexample, the UE 1B records a clock time at which the UE 1B connects tothe URN 2A. The UE 1B uses IP^(URN2A) _(UE1B) for a socket opened at orafter the clock time. Then, if all the sockets opened at or before theclock time are closed, this means that IP_(UE1B) is not used. The UE 1Bdetects this fact and notifies the URN 2A of this fact.

Thereafter, the URN 2A waits for a time to some extent (for example, 1second) and collectively transmit attachment requests related to the UEs1 connected on the downstream side of the URN 2A during the time to theDeNB 3A (Step S1016). That is, the URN 2A can avoid transmittance of anattachment request every time each UE 1 is connected to the downstreamof the URN 2A, by transmitting the attachment requests related to theplurality of UEs 1 at a time. Each attachment request includes anidentifier (for example, ID_(UE1B)), an IPv6 address (for example,IP_(UE1B)), IP^(UE) _(URN2A), and ID_(URN2A) of the UE 1B connected tothe URN 2A and information indicating that the connection is UEconnection to the virtual cell.

Then, the DeNB 3A receives the attachment request and transfers theattachment request to the MME 7 (Step S1018).

Next, the MME 7 receives the attachment request and transmits a defaultbearer creation request to the S-GW 5A (Step S1020). The default bearercreation request includes ID_(UE1B), IP_(UE1B), IP^(UE) _(URN2A), andID_(URN2A).

Then, the S-GW 5A receives the default bearer creation request andtransfers the default bearer creation request to the P-GW 6 (StepS1022).

Next, the P-GW 6 receives the default bearer creation request,associates the transfer destination of IP_(UE1B) with IP^(UE) _(URN2A),and transmits a default bearer creation response to the S-GW 5A (StepS1024). The default bearer creation response includes ID_(UE1B),IP_(UE1B), IP^(UE) _(URN2A), and ID_(URN2A).

Then, the S-GW 5A receives the default bearer creation response,associates the transfer destination of IP_(UE1B) with IP^(UE) _(URN2A),and transmits a default bearer creation response to the MME 7 (StepS1026).

Next, the MME 7 receives the default bearer creation response andtransmits attachment acceptance to the DeNB 3A (Step S1028). Theattachment acceptance includes ID_(UE1B), IP_(UE1B), IP^(UE) _(URN2A),and ID_(URN2A).

Then, the DeNB 3A receives the attachment acceptance, associates thetransfer destination of IP_(UE1B) with IP^(UE) _(URN2A), and transfersthe attachment acceptance to the URN 2A (Step S1030).

As a result, the P-GW 6, the S-GW 5A, and the DeNB 3A store the mappingtables illustrated in Tables 5, 6, and 7, respectively.

TABLE 5 (Mapping table stored in P-GW 6) End point IPv6 address Transferdestination Route URN IP^(UE) _(URN2A) GTP_(SGW5A) — Pref_(URN2A) SeeIP^(UE) _(URN2A) ID_(URN2A) IP_(UE1B) See IP^(UE) _(URN2A) ID_(URN2A)

TABLE 6 (Mapping table stored in S-GW 5A) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(DeNB3A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1B) See IP^(UE)_(URN2A) ID_(URN2A)

TABLE 7 (Mapping table stored in DeNB 3A) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(URN2A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1B) See IP^(UE)_(URN2A) ID_(URN2A)

The above mapping tables will be described. An entry on the third row isnewly added to each of the above mapping tables. According to the entryon the third row, the packet directed to IP_(UE1B) is transferred to thetransfer destination of the entry on the first row with the end pointIPv6 address of IP^(UE) _(URN2A) on the basis of “See IP^(UE) _(URN2A)”described in the transfer section. The packet is transferred to“GTP_(SGW5A)” by the P-GW 6 according to Table 5, is transferred to“GTP_(DeNB3A)” by the S-GW 5A according to Table 6, and is transferredto ‘GTP_(URN2A)” by the DeNB 3A according to Table 7. In this manner,the packet is transferred to the URN 2A. Then, the packet is transferredfrom the URN 2A to the UE 1B.

(4) Procedure for Connection of URN 2B which has not Yet Acquired IPv6Address to URN 2A

Hereinafter, a flow of processing performed in a case in which the URN2B that has not yet acquired the IPv6 address connects to the URN 2Aafter the aforementioned connection processing will be described. Theprocessing is executed in a case in which the power source of the URN 2Bis turned on in the vicinity of the URN 2A, for example.

FIG. 41 is a sequence diagram illustrating an example of a flow ofprocessing of connecting the URN 2B to the URN 2A according to theembodiment. The URN 2B, the URN 2A, the DeNB 3A, the MME 7, the S-GW 5A,and the P-GW 6 are involved in the sequence.

As illustrated in FIG. 41, the URN 2B establishes a wireless line withthe URN 2A first (Step S1102).

Then, the URN 2B transmits RS directed to a link local all-routermultiple-cast address (Step S1104). The source address of the RS is alink local address of the URN 2B.

Next, the URN 2A transmits RA directed to a link local address of theURN 2B (Step S1106). The RA includes the higher 64 bits (prefix) ofIP^(D) _(URN2A) and information indicating that the URN 2A is present inthe virtual cell.

Then, the URN 2B receives the RA and generates an IPv6 address IP^(U)_(URN2B) (Step S1108). In addition, the URN 2B sets IP^(UE) _(URN2B) tothe same value as IP^(U) _(URN2B).

Next, the URN 2B transmits an attachment request to the URN 2A (StepS1110). The attachment request includes an identifier ID_(URN2B) andIP^(U) _(URN2B) of the URN 2B.

Then, the URN 2A receives the attachment request and transmitsattachment acceptance to the URN 2B (Step S1112). The attachmentacceptance includes IP^(D) _(URN2A) and lower 64 bits (if-id) of IP^(U)_(URN2B).

Next, the URN 2B transmits RS to the URN 2A (Step S1114).

Then, the URN 2A receives the RS and transmits RA to the URN 2B (StepS1116). The RA includes the higher 64 bits (prefix) of IP^(D) _(URN2A).

Next, the URN 2B receives the RA and generates IP^(UE) _(URN2B) (StepS1118). As a result, IP^(U) _(URN2B) and IP^(UE) _(URN2B) become equalto each other.

Then, the URN 2B executes DHCP-PD with the URN 2A (Step S1120).

Next, the URN 2A cuts Pref_(URN2B) that is a prefix of /64, for example,of Pref_(URN2A) and assigns Pref_(URN2B) to the URN 2B as a result ofexecuting the DHCP-PD (Step S1122). The URN 2B generates an IPv6 addressIP^(D) _(URN2B) from Pref_(URN2B) and uses the IPv6 address IP^(D)_(URN2B) for communication in the nested virtual cell on the downstreamside. The URN 2A sets the transfer destination of Pref_(URN2B) to IP^(U)_(URN2B).

Thereafter, the URN 2A waits for a time to some extent (for example, 1second) and collectively transmit attachment requests related to theURNs 2 connected on the downstream side of the URN 2A during the time tothe DeNB 3A (Step S1124). That is, the URN 2A can avoid transmittance ofan attachment request every time each URN 2 is connected to thedownstream of the URN 2A, by transmitting the attachment requestsrelated to the plurality of URNs 2 at a time. Each attachment requestincludes an identifier (for example, ID_(URN2B)) and an IPv6 address(for example, IP_(URN2B)) of the URN 2B connected to the URN 2A, theID_(URN2A) and information indicating that the connection is RNconnection to the virtual cell.

Then, the DeNB 3A receives the attachment request and transfers theattachment request to the MME 7 (Step S1126).

Next, the MME 7 receives the attachment requests and transmitsattachment acceptance to the DeNB 3A (Step S1128).

Then, the DeNB 3A receives the attachment accept and transfers theattachment acceptance to the URN 2A (Step S1130).

As a result of the processing, there is no change in the mapping tablestored in the P-GW 6, the S-GW 5A, and the DeNB 3A. That is, the amountof information stored in the P-GW 6, the S-GW 5A, and the DeNB 3A doesnot depend on the number of URNs 2 with power sources that have beenturned on in the virtual cell provided by the URN 2A.

(5) Procedure for Connection of URN 2C which has Already Acquired IPv6Address to URN 2A

Hereinafter, a flow of processing performed in a case in which the URN2C that has acquired an IPv6 address connects to the URN 2A after theaforementioned connection processing will be described. For example, itis assumed that the URN 2C has obtained the IPv6 address IP^(UE)_(URN2C) and the prefix Pref_(URN2C) before the connection to the URN2A. In addition, it is assumed that the UE 1D has been connected to theURN 2C, and that the UE 1D has obtained IP_(UE1D) that is the IPv6address that belongs to Pref_(URN2C). The processing can be executed ina case in which the virtual cell that has been connected to the DeNB 3is connected to the downstream of the URN 2A, for example.

FIG. 42 is a sequence diagram illustrating an example of a flow ofprocessing of connecting the URN 2C to the URN 2A according to theembodiment. The URN 2C, the URN 2A, the DeNB 3A, the MME 7, the S-GW 5A,and the P-GW 6 are involved in the sequence.

As illustrated in FIG. 42, the URN 2C establishes a wireless line withthe URN 2A first (Step S1202).

Then, the URN 2C transmits RS directed to a link local all-routermultiple-cast address (Step S1204). The source address of the RS is alink local address of the URN 2C.

Next, the URN 2A transmits RA directed to a link local address of theURN 2C (Step S1206). The RA includes the prefix of /64 that belongs toPref_(URN2A), for example, Pref^(URN2A) _(URN2C).

Then, the URN 2C receives the RA and generates IP^(U) _(URN2C) (StepS1208).

Next, the URN 2C transmits an attachment request to the URN 2A (StepS1210). The attachment request includes an identifier ID_(URN2C),IP^(UE) _(URN2C), and Pref_(URN2C) of the URN 2C.

Then, the URN 2A receives the attachment request and transfers theattachment request to the DeNB 3A (Step S1212). At that time, the URN 2Aadds IP^(UE) _(URN2A) and ID_(URN2A) to the attachment request.

Next, the DeNB 3A receives the attachment requests and transfers theattachment requests to the MME 7 (Step S1214).

Then, the MME 7 receives the attachment request and transmits a defaultbearer creation request to the S-GW 5A (Step S1216). The default bearercreation request includes ID_(URN2A), ID_(URN2C), IP^(UE) _(URN2A),IP^(UE) _(URN2C), and Pref_(URN2C).

Next, the S-GW 5A receives the default bearer creation request andtransfers the default bearer creation request to the P-GW 6 (StepS1218).

Then, the P-GW 6 associates transfer destinations of IP^(UE) _(URN2C)and Pref_(URN2C) with IP^(UE) _(URN2A). Then, the P-GW 6 transmits adefault bearer creation response to the S-GW 5A (Step S1220). Thedefault bearer creation response includes ID_(URN2A), IP^(UE) _(URN2A),IP^(UE) _(URN2C), and Pref_(URN2C).

Next, the S-GW 5A receives the default bearer creation response andassociates transfer destinations of IP^(UE) _(URN2C) and Pref_(URN2C)with IP^(UE) _(URN2A). Then, the S-GW 5A transmits the default bearercreation response to the MME 7 (Step S1222).

Then, the MME 7 receives the default bearer creation response andtransmits attachment acceptance to the DeNB 3A (Step S1224). Theattachment acceptance includes ID_(URN2A), IP^(UE) _(URN2A), IP^(UE)_(URN2C), and Pref_(URN2C).

Next, the DeNB 3A receives the attachment request and associates thetransfer destinations of IP^(UE) _(URN2C) and Pref_(URN2C) with IP^(UE)_(URN2A). Then, the DeNB 3A transmits the default bearer creationresponse to the URN 2A (Step S1226).

Then, the URN 2A receives the attachment acceptance and forms a GTPtunnel with the URN 2C. End points of the GTP tunnel are IP^(D) _(URN2A)and IP^(U) _(URN2C). Next, the URN 2A associates the transferdestinations of IP^(DE) _(URN2C) and Pref_(URN2C) with the GTP tunnel.Then, the URN 2A transmits attachment acceptance to the URN 2C (StepS1228). The attachment acceptance includes the lower 64 bits (if-id) ofIP^(UE) _(URN2C) and IP^(UE) _(URN2A).

Next, the URN 2C receives the attachment acceptance and obtains thelower 64 bits (if-id) of IP^(UE) _(URN2C). Then, the URN 2C forms a GTPtunnel with the URN 2A (Step S1230). End points of the GTP tunnel areIP^(U) _(URN2C) and IP^(D) _(URN2A).

Then, the URN 2C transmits RS to the URN 2A (IP^(UE) _(URN2A)) (StepS1232).

Next, the URN 2A receives the RS and transmits RA to the URN 2C (StepS1234). The RA includes the higher 64 bits (prefix) of IP^(UE) _(URN2C).

Then, the URN 2C receives the RA and checks that IP^(UE) _(URN2C) isavailable (Step S1236).

As a result, the P-GW 6, the S-GW 5A, and the DeNB 3A store the mappingtables illustrated in Tables 8, 9, and 10, respectively.

TABLE 8 (Mapping table stored in P-GW 6) End point IPv6 address Transferdestination Route URN IP^(UE) _(URN2A) GTP_(SGW5A) — Pref_(URN2A) SeeIP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE) _(URN2A) ID_(URN2A)IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A) Pref_(URN2C) SeeIP^(UE) _(URN2A) ID_(URN2A)

TABLE 9 (Mapping table stored in S-GW 5A) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(DeNB3A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)

TABLE 10 (Mapping table stored in DeNB 3A) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(URN2A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)

The above mapping tables will be described. Entries on the fourth andfifth rows are newly added to each of the above mapping tables.According to the entry on the fourth row, the packet directed to IP^(UE)_(URN2C) is transferred to the transfer destination of the entry on thefirst row with the end point IPv6 address of IP^(UE) _(URN2A) on thebasis of “See IP^(UE) _(URN2A)” described in the transfer section. Thepacket is transferred to “GTP_(SGW5A)” by the P-GW 6 according to Table8, is transferred to “GTP_(DeNB3A)” by the S-GW 5A according to Table 9,and is transferred to ‘GTP_(URN2A)” by the DeNB 3A according to Table10. In this manner, the packet is transferred to the URN 2A. Thereafter,the packet is transferred from the URN 2A to the URN 2C.

According to the entry of the fifth row, a packet with a destination IPaddress with a prefix portion that is Pref_(URN2C) is transferred to atransfer destination of an entry of the first row with an end point IPv6address that is IP^(UE) _(URN2A) on the basis of “See IP^(UE) _(URN2A)”described in the transfer destination section. The packet is transferredto “GTP_(SGW5A)” by the P-GW 6 according to Table 8, is transferred to“GTP_(DeNB3A)” by the S-GW 5A according to Table 9, and is transferredto ‘GTP_(URN2A)” by the DeNB 3A according to Table 10. In this manner,the packet is transferred to the URN 2A. Thereafter, the packet istransferred from the URN 2A to the URN 2C.

(6) Procedure for Connection of URN 2D which has Already Acquired IPv6Address to URN 2A

Hereinafter, a flow of processing performed in a case in which the URN2D that has acquired an IPv6 address connects to the URN 2A after theaforementioned connection processing will be described. For example, itis assumed that the URN 2D has obtained the IPv6 address IP^(UE)_(URN2D) and the prefix Pref_(URN2D) before the connection to the URN2A. In addition, it is assumed that the UE 1E has been connected to theURN 2D, and that the UE 1E has obtained IP_(UE1E) that is the IPv6address that does not belong to Pref_(URN2D). The processing can beexecuted in a case in which the virtual cell that has been connected tothe DeNB 3 is connected to the downstream of the URN 2A, for example.

FIG. 43 is a sequence diagram illustrating an example of a flow ofprocessing of connecting the URN 2D to the URN 2A according to theembodiment. The URN 2D, the URN 2A, the DeNB 3A, the MME 7, the S-GW 5A,and the P-GW 6 are involved in the sequence.

As illustrated in FIG. 43, the URN 2D establishes a wireless line withthe URN 2A first (Step S1302).

Then, the URN 2D transmits RS directed to a link local all-routermultiple-cast address (Step S1304). The source address of the RS is alink local address of the URN 2D.

Next, the URN 2A receives the RS, and transmits RA directed to a linklocal address of the URN 2D (Step S1306). The RA includes the prefix of/64 that belongs to Pref_(URN2A), for example, Pref^(URN2A) _(URN2D).

Then, the URN 2D receives the RA and generates IP^(U) _(URN2D) (StepS1308).

Next, the URN 2D transmits an attachment request to the URN 2A (StepS1310). The attachment request includes an identifier ID_(URN2D), IP^(U)_(URN2D), Pref_(URN2D), and IP_(UE1E) of the URN 2D.

Then, the URN 2A receives the attachment request and transfers theattachment request to the DeNB 3A (Step S1312). At that time, the URN 2Aadds IP^(UE) _(URN2A) and ID_(URN2A) to the attachment request.

Next, the DeNB 3A receives the attachment requests and transfers theattachment requests to the MME 7 (Step S1314).

Then, the MME 7 receives the attachment request and transmits a defaultbearer creation request to the S-GW 5A (Step S1316). The default bearercreation request includes ID_(URN2A), ID_(URN2D), IP^(UE) _(URN2A),IP^(UE) _(URN2D), Pref_(URN2D), and IP_(UE1E).

Next, the S-GW 5A receives the default bearer creation request andtransfers the default bearer creation request to the P-GW 6 (StepS1318).

Then, the P-GW 6 associates the transfer destinations of IP^(UE)_(URN2D) and Pref_(URN2D) with IP^(UE) _(URN2A). In addition, the P-GW 6associates the transfer destination of UE 1E with Pref_(URN2D). Then,the P-GW 6 transmits the default bearer creation response to the S-GW 5A(Step S1320). The default bearer creation response includes ID_(URN2A),IP^(UE) _(URN2A), IP^(UE) _(URN2D), Pref_(URN2D), and IP_(UE1E).

Next, the S-GW 5A receives the default bearer creation response andassociates the transfer destinations of IP^(UE) _(URN2D) andPref_(URN2D) with IP^(UE) _(URN2A). In addition, the S-GW 5A associatesthe transfer destination of the UE 1E with Pref_(URN2D). In addition,the S-GW 5A transmits the default bearer creation response to the MME 7(Step S1322).

Then, the MME 7 receives the default bearer creation response andtransmits attachment acceptance to the DeNB 3A (Step S1324). Theattachment acceptance includes ID_(URN2A), IP^(UE) _(URN2A), IP^(UE)_(URN2D), Pref_(URN2D), and IP_(UE1E).

Next, the DeNB 3A receives the attachment acceptance associates thetransfer destinations of IP^(UE) _(URN2D) and Pref_(URN2D) with IP^(UE)_(URN2A). In addition, the DeNB 3A associates the transfer destinationof the UE 1E with Pref_(URN2D). Then, the DeNB 3A transmits the defaultbearer creation response to the URN 2A (Step S1326).

Then, the URN 2D receives the attachment acceptance and forms a GTPtunnel with the URN 2D. End points of the GTP tunnel are IP^(D) _(URN2A)and IP^(U) _(URN2D). Next, the URN 2A associates the transferdestinations of IP^(UE) _(URN2D) and Pref_(URN2D) with the GTP tunnel.Then, the URN 2A transmits attachment acceptance to the URN 2D (StepS1328). The attachment acceptance includes the lower 64 bits (if-id) ofIP^(UE) _(URN2A) and IP^(UE) _(URN2A).

Next, the URN 2D receives the attachment acceptance and obtains thelower 64 bits (if-id) of IP^(UE) _(URN2D). Then, the URN 2D forms a GTPtunnel with the URN 2A (Step S1330). End points of the GTP tunnel areIP^(U) _(URN2D) and IP^(D) _(URN2A).

Then, the URN 2D transmits RS to the URN 2A (IP^(UE) _(URN2A)) (StepS1332).

Next, the URN 2D receives the RS and transmits RA to the URN 2C (StepS1334). The RA includes the higher 64 bits (prefix) of IP^(UE) _(URN2D).

Then, the URN 2D receives the RA and checks that IP^(UE) _(URN2D) isavailable (Step S1336).

As a result, the P-GW 6, the S-GW 5A, and the DeNB 3A store the mappingtables illustrated in Tables 11, 12, and 13, respectively.

TABLE 11 (Mapping table stored in P-GW 6) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(SGW5A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A) IP^(UE) _(URN2D) SeeIP^(UE) _(URN2A) ID_(URN2A) Pref_(URN2D) See IP^(UE) _(URN2A) ID_(URN2A)IP^(UE) _(UE1E) See Pref_(URN2D) ID_(URN2A)

TABLE 12 (Mapping table stored in S-GW 5A) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(DeNB3A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A) IP^(UE) _(URN2D) SeeIP^(UE) _(URN2A) ID_(URN2A) Pref_(URN2D) See IP^(UE) _(URN2A) ID_(URN2A)IP^(UE) _(UE1E) See Pref_(URN2D) ID_(URN2A)

TABLE 13 (Mapping table stored in DeNB 3A) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(URN2A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A) IP^(UE) _(URN2D) SeeIP^(UE) _(URN2A) ID_(URN2A) Pref_(URN2D) See IP^(UE) _(URN2A) ID_(URN2A)IP^(UE) _(UE1E) See Pref_(URN2D) ID_(URN2A)

The above mapping tables will be described. Entries on the sixth toeighth rows are newly added to each of the above mapping tables.According to the entry on the sixth row, the packet directed to IP^(UE)_(URN2D) is transferred to the transfer destination of the entry on thefirst row with the end point IPv6 address of IP^(UE) _(URN2A) on thebasis of “See IP^(UE) _(URN2A)” described in the transfer section. Thepacket is transferred to “GTP_(SGW5A)” by the P-GW 6 according to Table11, is transferred to “GTP_(DeNB3A)” by the S-GW 5A according to Table12, and is transferred to ‘GTP_(URN2A)” by the DeNB 3A according toTable 13. In this manner, the packet is transferred to the URN 2A.Thereafter, the packet is transferred from the URN 2D to the URN 2C.

According to the entry of the seventh row, a packet with a destinationIP address with a prefix portion that is Pref_(URN2D) is transferred toa transfer destination of an entry of the first row with an end pointIPv6 address that is IP^(UE) _(URN2A) on the basis of “See IP^(UE)_(URN2A)” described in the transfer destination section. The packet istransferred to “GTP_(SGW5A)” by the P-GW 6 according to Table 11, istransferred to “GTP_(DeNB3A)” by the S-GW 5A according to Table 12, andis transferred to ‘GTP_(URN2A)” by the DeNB 3A according to Table 13. Inthis manner, the packet is transferred to the URN 2A. Thereafter, thepacket is transferred from the URN 2A to the URN 2D.

According to the entry on the eighth row, the packet directed to IPUE1Eis transferred to the transfer destination of the entry on the first rowwith the end point IPv6 address of IP^(UE) _(URN2A) on the basis of “SeePref_(URN2D)” described in the transfer section and further on the basisof “See IP^(UE) _(URN2A)” described in the transfer section of the entryon the seventh row with the end point IPv6 address of Pref_(URN2D). Thepacket is transferred to “GTP_(SGW5A)” by the P-GW 6 according to Table11, is transferred to “GTP_(DeNB3A)” by the S-GW 5A according to Table12, and is transferred to ‘GTP_(URN2A)” by the DeNB 3A according toTable 13. In this manner, the packet is transferred to the URN 2A.Thereafter, the packet is transferred from the URN 2A to the URN 2D andthen from the URN 2D to the UE 1E.

(7) Procedure for Handover in S-GW 5

Hereinafter, a flow of processing performed in a case in which the URN2A performs handover from the DeNB 3A to the DeNB 3B in a state in whichthe UE 1A, the UE 1B, the URN 2B and the UE 1C, the URN 2C and the UE1D, and the URN 2D and the UE 1E are connected on the downstream side ofthe URN 2A by the aforementioned connection processing will bedescribed.

FIG. 44 is a sequence diagram illustrating an example of a flow ofhandover processing to the DeNB 3B performed by the URN 2A according tothe embodiment. The URN 2A, the DeNB 3A, the DeNB 3B, the MME 7, theS-GW 5A, and the P-GW 6 are involved in the sequence.

As illustrated in FIG. 44, the DeNB 3A decides to execute handover tothe DeNB 3B by the URN 2A first (Step S1402).

Then, the DeNB 3A transmits a handover request to the DeNB 3B (StepS1404). The handover request includes ID_(URN2A).

Next, the DeNB 3B transmits a handover request ACK to the DeNB 3A (StepS1406). The handover request ACK includes ID_(URN2A).

Then, the URN 2A establishes a wireless line with the DeNB 3B (StepS1408).

Next, the URN 2A transmits RS directed to a link local all-routermultiple-cast address (Step S1410). The source address of the RS is alink local address of the URN 2A.

Then, the DeNB 3B receives the RS and transmits RA directed to the linklocal address of the URN 2A (Step S1412). The RA includes higher 64 bits(prefix) of IP^(D) _(DeNB3B).

Next, the URN 2A receives the RA and generates an IPv6 address IP2 ^(U)_(URN2A) (Step S1414). The IP2 ^(U) _(URN2A) is used when the URN 2Aestablishes a GTP tunnel with the DeNB 3B.

Then, the URN 2A transmits an attachment request to the DeNB 3B (StepS1416). The attachment request includes the identifier ID_(URN2A), IP2^(U) _(URN2A), and IP^(UE) _(URN2A) of the URN 2A.

Next, the DeNB 3B receives the attachment request and transmits a pathswitch request to the MME 7 (Step S1418). The path switch requestincludes ID_(URN2A), IP2 ^(U) _(URN2A), and IP^(UE) _(URN2A).

Then, the MME 7 receives the path switch request and transmits a bearermodification request to the S-GW 5A (Step S1420). The bearermodification request includes ID_(URN2A), IP2 ^(U) _(URN2A), and IP^(UE)_(URN2A).

Next, the S-GW 5A receives the bearer modification request, detects thatthe URN 2A has performed the handover with the DeNB 3 on the downstreamside of the S-GW 5A, releases the GTP tunnel established between theS-GW 5A and the DeNB 3A, and forms the GTP tunnel between the S-GW 5Aand the DeNB 3B. End points of the GTP tunnel are IP^(D) _(SGW5A) andIP^(U) _(DeNB) 3B. Then, the S-GW 5A associates the transfer destinationof IP^(UE) _(URN2A) with the GTP tunnel. Then, the S-GW 5A transmits abearer modification response to the MME 7 (Step S1422). The bearermodification response includes ID_(URN2A), IP2 ^(U) _(URN2A), IP^(UE)_(URN2A), and the entry with a route URN of URN 2A in the mapping table.

Then, the MME 7 receives the bearer modification response and transmitsa path switch request ACK to the DeNB 3B (Step S1424). The path switchrequest ACK includes ID_(URN2A), IP2 ^(U) _(URN2A), IP^(UE) _(URN2A),and an entry with a route URN of URN 2A in the mapping table of the S-GW5A.

Next, the DeNB 3B receives the path switch request ACK and forms a GTPtunnel between the DeNB 3B and the S-GW 5A. End points of the GTP tunnelare IP^(U) _(DeNB3B) and IP^(D) _(SGW5A). Further, the DeNB 3B forms aGTP tunnel with the URN 2A. End points of the GTP tunnel are IP^(D)_(DeNB3B) and IP^(U) _(URN2A). Next, the DeNB 3B registers mapping tableentries included in the attachment acceptance in the mapping table ofthe DeNB 3B itself. Further, the DeNB 3B associates the transferdestination of IP^(UE) _(URN2A) with the GTP tunnel to the URN 2A. Next,the DeNB 3B transmits attachment acceptance to the URN 2A (Step S1426).The attachment acceptance includes the lower 64 bits (if-id) of IP^(UE)_(URN2A).

As a result of the aforementioned operations, GTP tunnels areestablished among the URN 2A, the DeNB 3B, and the S-GW 5A (Step S1428).In addition, the GTP tunnel between the S-GW 5A and the P-GW 6 ismaintained.

Then, the URN 2A receives the attachment acceptance and transmits RS tothe P-GW 6 in order to obtain an IPv6 address for operating as a UE(Step S1430).

Next, the P-GW 6 receives the RS and transmits RA to the URN 2A (StepS1432). The RA includes the higher 64 bits (prefix) of IP^(UE) _(URN2A).

Then, the URN 2A receives the RA and confirms that IP^(UE) _(URN2A) isavailable (Step S1434).

As a result, the P-GW 6, the S-GW 5A, and the DeNB 3B store the mappingtables illustrated in Tables 14, 15, and 16, respectively.

TABLE 14 (Mapping table stored in P-GW 6) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(SGW5A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A) IP^(UE) _(URN2D) SeeIP^(UE) _(URN2A) ID_(URN2A) Pref_(URN2D) See IP^(UE) _(URN2A) ID_(URN2A)IP^(UE) _(UE1E) See Pref_(URN2D) ID_(URN2A)

TABLE 15 (Mapping table stored in S-GW 5A) Endpoint IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(DeNB3B) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A) IP^(UE) _(URN2D) SeeIP^(UE) _(URN2A) ID_(URN2A) Pref_(URN2D) See IP^(UE) _(URN2A) ID_(URN2A)IP^(UE) _(UE1E) See Pref_(URN2D) ID_(URN2A)

TABLE 16 (Mapping table stored in DeNB 3B) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(URN2A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A) IP^(UE) _(URN2D) SeeIP^(UE) _(URN2A) ID_(URN2A) Pref_(URN2D) See IP^(UE) _(URN2A) ID_(URN2A)IP^(UE) _(UE1E) See Pref_(URN2D) ID_(URN2A)

The above mapping tables will be described. If Table 11 and Table 14 arecompared, these tables are the same, and there is no change caused bythe handover. If Table 12 and Table 15 are compared, the transferdestination of the entry on the first row changes from “GTP_(DeNB3A)” to“GTP_(DeNB3B)”. That is, the S-GW 5A may update only the entry on thefirst row in the mapping table during the handover in the S-GW 5A. IfTable 13 and Table 16 are compared, these tables are the same. The entryon the first row in the mapping table illustrated in Table 16 isregistered by the DeNB 3B. Meanwhile, the entries with the descriptionof “ID_(URN2A)” in the sections of the route URN in the mapping tableillustrated in Table 16, that is, all the entries in and below thesecond rows are taken over through the handover. That is, the DeNB 3Bcan omit a part of processing of generating the mapping table by takingover the mapping table during the handover. In this manner, it ispossible to significantly reduce signaling for position registration andthe like of the subordinate UEs 1 of the URN 2 since resetting of thetransfer destination is completed by updating or taking over a smallpart of the mapping table during the handover.

(8) Procedure for Handover Between S-GWs 5

Hereinafter, a flow of processing performed in a case in which the URN2A performs handover from the DeNB 3A to the DeNB 3C in a state in whichthe UE 1A, the UE 1B, the URN 2B and the UE 1C, the URN 2C and the UE1D, and the URN 2D and the UE 1E are connected to the downstream of theURN 2A will be described.

FIG. 45 is a sequence diagram illustrating an example of a flow ofhandover processing to the DeNB 3C performed by the URN 2A according tothe embodiment. The URN 2A, the DeNB 3A, the DeNB 3C, the MME 7, theS-GW 5A, the S-GW 5B, and the P-GW 6 are involved in the sequence.

As illustrated in FIG. 45, the DeNB 3A decides to execute handover tothe DeNB 3C by the URN 2A first (Step S1502).

Then, the DeNB 3A transmits a handover request to the DeNB 3C (StepS1504). The handover request includes ID_(URN2A).

Next, the DeNB 3C transmits a handover request ACK to the DeNB 3A (StepS1506). The handover request ACK includes ID_(URN2A).

Then, the URN 2A establishes a wireless line with the DeNB 3C (StepS1508).

Next, the URN 2A transmits RS directed to a link local all-routermultiple-cast address (Step S1510). The source address of the RS is alink local address of the URN 2A.

Then, the DeNB 3C receives the RS, and then transmits RA directed to thelink local address of the URN 2A (Step S1512). The RA includes higher 64bits (prefix) of IP^(D) _(DeNB3C).

Next, the URN 2A receives the RA and generates an IPv6 address IP3 ^(U)_(URN2A) (Step S1514). The IP3 ^(U) _(URN2A) is used when the URN 2Aestablishes a GTP tunnel with the DeNB 3C.

Then, the URN 2A transmits an attachment request to the DeNB 3C (StepS1516). The attachment request includes the identifier ID_(URN2A), IP3^(U) _(URN2A), and IP^(UE) _(URN2A) of the URN 2A.

Next, the DeNB 3C receives the attachment request and transmits a pathswitch request to the MME 7 (Step S1518). The path switch requestincludes ID_(URN2A), IP3 ^(U) _(URN2A), and IP^(UE) _(URN2A).

Then, the MME 7 receives the path switch request and transmits a bearermodification request to the S-GW 5B (Step S1520). The bearermodification request includes ID_(URN2A), IP3 ^(U) _(URN2A), and IP^(UE)_(URN2A).

Next, the S-GW 5B receives the bearer modification request and transfersthe bearer modification request to the P-GW 6 (Step S1522).

Then, the P-GW 6 receives the bearer modification request, detects thatthe URN 2A has performed the handover between the S-GW 5A and the S-GW5B, releases the GTP tunnel established between the P-GW 6 and the S-GW5A, and forms a GTP tunnel between the P-GW 6 and the S-GW 5B. Endpoints of the GTP tunnel are IP^(D) _(PGW6) and IP^(U) _(SGW5B). Inaddition, the P-GW 6 associates the transfer destination of IP^(UE)_(URN2A) with the GTP tunnel. Then, the P-GW 6 transmits a bearermodification response to the S-GW 5B (Step S1524). The bearermodification response includes ID_(URN2A), IP3 ^(U) _(URN2A), IP^(UE)_(URN2A), and entries with a route URN of URN 2A in the mapping table.

Next, the S-GW 5B receives the bearer modification response and forms aGTP tunnel between the P-GW 6 and the S-GW 5B. End points of the GTPtunnel are IP^(U) _(SGW5B) and IP^(D) _(PGW6). Further, the S-GW 5Bforms a GTP tunnel with the DeNB 3C. End points of the GTP tunnel areIP^(D) _(SGW5B) and IP^(U) _(DeNB3C). Next, the S-GW 5B registers themapping table entry included in the bearer modification response in themapping table of the S-GW 5B itself. Further, the S-GW 5B associates thetransfer destination of IP^(UE) _(URN2A) with the GTP tunnel to the DeNB3C. Next, the S-GW 5B transfers the bearer modification response to theMME 7 (Step S1526). The bearer modification response includesID_(URN2A), IP3 ^(U) _(URN2A), IP^(UE) _(URN2A), lower 64 bits (if-id)of IP^(UE) _(URN2A), and entries with a route URN of URN 2A in themapping table.

Then, the MME 7 receives the bearer modification response and transmitsa path switch request ACK to the DeNB 3C (Step S1528). The path switchrequest ACK includes ID_(URN2A), IP3 ^(U) _(URN2A), IP^(UE) _(URN2A),lower 64 bits (if-id) of IP^(UE) _(URN2A), and entries with a route URNof URN 2A in the mapping table of the S-GW 5B.

Next, the DeNB 3C receives the path switch request ACK and forms a GTPtunnel between the DeNB 3C and the S-GW 5B. End points of the GTP tunnelare IP^(U) _(DeNB3C) and IP^(D) _(SGW5B). Further, the DeNB 3C forms aGTP tunnel with the URN 2A. End points of the GTP tunnel are IP^(D)_(DeNB3C) and IP^(U) _(URN2A). Next, the DeNB 3C registers mapping tableentries included in the pas switch request ACK in the mapping table ofthe DeNB 3C itself. Further, the DeNB 3C associates the transferdestination of IP^(UE) _(URN2A) with the GTP tunnel to the URN 2A. Next,the DeNB 3C transfers attachment acceptance to the URN 2A (Step S1530).The attachment acceptance includes the lower 64 bits (if-id) of IP^(UE)_(URN2A).

As a result of the aforementioned processing, the GTP tunnels areestablished among the URN 2A, the DeNB 3C, the S-GW 5B, and the P-GW 6(Step S1532).

Then, the URN 2A receives the attachment acceptance and transmits RS tothe P-GW 6 in order to obtain an IPv6 address for operating as a UE(Step S1534).

Next, the P-GW 6 receives the RS and transmits RA to the URN 2A (StepS1536). The RA includes the higher 64 bits (prefix) of IP^(UE) _(URN2A).

Then, the URN 2A receives the RA and confirms that IP^(UE) _(URN2A) isavailable (Step S1538).

As a result, the P-GW 6, the S-GW 5B, and the DeNB 3C store the mappingtables illustrated in Tables 17, 18, and 19, respectively.

TABLE 17 (Mapping table stored in P-GW 6) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(SGW5B) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A) IP^(UE) _(URN2D) SeeIP^(UE) _(URN2A) ID_(URN2A) Pref_(URN2D) See IP^(UE) _(URN2A) ID_(URN2A)IP^(UE) _(UE1E) See Pref_(URN2D) ID_(URN2A)

TABLE 18 (Mapping table stored in S-GW 5B) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(DeNB3C) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A) IP^(UE) _(URN2D) SeeIP^(UE) _(URN2A) ID_(URN2A) Pref_(URN2D) See IP^(UE) _(URN2A) ID_(URN2A)IP^(UE) _(UE1E) See Pref_(URN2D) ID_(URN2A)

TABLE 19 (Mapping table stored in DeNB 3C) End point IPv6 addressTransfer destination Route URN IP^(UE) _(URN2A) GTP_(URN2A) —Pref_(URN2A) See IP^(UE) _(URN2A) ID_(URN2A) IP_(UE1A) See IP^(UE)_(URN2A) ID_(URN2A) IP^(UE) _(URN2C) See IP^(UE) _(URN2A) ID_(URN2A)Pref_(URN2C) See IP^(UE) _(URN2A) ID_(URN2A) IP^(UE) _(URN2D) SeeIP^(UE) _(URN2A) ID_(URN2A) Pref_(URN2D) See IP^(UE) _(URN2A) ID_(URN2A)IP^(UE) _(UE1E) See Pref_(URN2D) ID_(URN2A)

The above mapping tables will be described. If Tables 14 and Table 17are compared, the transfer destination of the entry on the first rowchanges from “GTP_(SGW5A)” to “GTP_(SGW5B)”. That is, the P-GW 6 mayupdate only the entry on the first row in the mapping table for thehandover over the S-GW 5. If Table 15 and Table 18 are compared, thetransfer destination of the entry on the first row is changed from“GTP_(DeNB3B)” to “GTP_(DeNB3C)”. The entry on the first row in themapping table in Table 18 is registered by the S-GW 5B. Meanwhile,entries with description of “ID_(URN2A)” in the section of the route URNin the mapping table illustrated in Table 18, that is, all the entriesin and below the second row are taken over through the handover. Thatis, the S-GW 5B can omit a part of the processing of generating themapping table by taking over the mapping table during the handover. IfTable 16 and Table 19 are compared, these tables are the same. The entryon the first row in the mapping table illustrated in Table 19 isregistered by the DeNB 3C. Meanwhile, entries with description of“ID_(URN2A)” in the section of the route URN in the mapping tableillustrated in Table 19, that is, all the entries in and below thesecond row is taken over through the handover. That is, the DeNB 3C canomit a part of the processing of generating the mapping table by takingover the mapping table during the handover. In this manner, it ispossible to significantly reduce signaling or position registration andthe like of the subordinate UEs 1 of the URN 2 since resetting of thetransfer destination is completed by updating or taking over a smallpart of the mapping table even for the handover over the S-GW 5.

<4.3. Effects>

Hereinafter, main effects of the aforementioned protocol will bedescribed.

For example, the aforementioned protocol is a protocol adapted to a 3GPParchitecture. For example, functions assigned to the P-GW, the S-GW, theMME, the eNB, the DeNB, the RN, and the UE are maintained. In addition,interfaces defined among these devices are maintained. In addition,message sequences defined among these devices are maintained.

In addition, the UE1 that has already acquired the IPv6 address cancontinue communication even after the connection to the virtual cell.

In addition, the DHCP-PD is used in the protocol. In this manner, it ispossible to realize the nested virtual cell. In addition, the amount ofinformation to be stored in the P-GW 6, the S-GW 5, or the DeNB 3 doesnot depend on the number of UEs 1 or URNs 2 that have obtained IPv6addresses in the virtual cell by using the DHCP-PD.

In addition, the mapping tables are utilized in the protocol. In thismanner, the number of items to be updated when the virtual cell performshandover decreases. In addition, only the URN 2 performs signaling whenthe URN 2 performs handover between the DeNBs 3. In this manner, thesubordinate UEs 1 and the like of the URN 2 are prevented fromindividually performing signaling, and the amount of signaling issuppressed during the handover.

In addition, signaling traffic during the handover of the URN 2 does notincrease depending on the number of UEs 1 or the URNs 2 that haveobtained the IPv6 addresses in the virtual cell.

In addition, the URN 2 can collectively perform registration of aplurality of UEs or the URNs 2 connected to the virtual cell in the MME7 instead of registering them one by one. In this manner, it is possibleto suppress the number of signaling packets.

In addition, it is possible to state that a route of communicationperformed by the UEs 1 and the URN 2 in the 3GPP network includes nodetour routing and is optimal.

In addition, no tunneling is used other than the tunneling defined by3GPP in this protocol. Accordingly, header overhead does not increasewhen this protocol is introduced.

<<5. Use Case>>

The aforementioned protocol can be applied to a variety of use cases.

(1) Realization of Network Service During Movement

In a case in which the URN 2 is mounted on a public transportation suchas a bus or a train, for example, the URN 2 can solve discontinuity andthe like of access, which accompany the movement, by providing localcontent to the UEs 1 of the passengers from a server that is connectedto the URN 2. In addition, it is possible to realize movingtransmittivity for services from the DeNB 3 to which the URN 2 isconnected or a server connected to an entity on a core network. Theserver connected to the URN 2 is effectively used for services thatrequire a short delay time. In addition, in a case in which a nestedvirtual cell formed by a URN 2 of a passenger is connected to the URN 2mounted on the public transportation, continuity of the nested virtualcell to the network is continued by only the URN 2 of the passengerperforming connection processing. Since a situation in which all the UEs1 on board perform processing of establishing connection to the networkis avoided, an improvement in wireless utilization efficiency isrealized.

(2) Improvement in Wireless Utilization Efficiency in Environment inwhich UEs 1 are Crowded

In an environment in which the density of the UEs 1 is significantlyhigh, such as in downtown or during an event, the improvement in thewireless utilization efficiency is realized, and more UEs 1 can beaccommodated by providing the UEs 1 RN functions and realizing movingtransmittivity of other UEs in the surroundings.

(3) Application to Security System

It is possible to provide an advanced security system to a movingenvironment by a camera being connected to the URN 2 that is mounted ona moving transportation. For example, an advanced security system isrealized by accumulating captured images in a server connected to theURN 2, performing data analysis thereon, and as needed, performing, bythe URN 2, communication with an entity in the core network or acalculation resource on the cloud.

(4) Realization of Dynamic Operating Service of Cognitive WirelessSystem

A cognitive wireless system is a system that provides an access networkutilizing frequencies by utilizing frequency database for managingavailable frequencies for the respective areas. For example, it isconsidered that functions as an access point (that is, a base station)of the cognitive wireless system are mounted on the URN 2. In that case,the URN 2 can specify an available frequency at a current position fromthe frequency database by utilizing location information (GPSinformation, wireless base station information, or the like) and thenprovides a virtual cell by utilizing the frequency. In addition, it alsobecomes possible to provide a network access service via the URN 2 or adevice-to-device (D2D) communication service between the UE 1 and the UE1 or between the URN 2 and the UE 1.

(5) Realization of Dynamic Operating Services by Drone

It is possible to provide wireless services to various device groups ina flight area by mounting functions of the URN 2 providing a virtualcell on a drone. The drone that functions as the URN 2 will also bereferred to as a king drone in the following description. The king dronemay have a function of a cognitive wireless system and may specify anavailable frequency in a flying area through communication with afrequency database. The device groups connected to the virtual cell maybe sensor devices, for example. In regard to agriculture, for example, ageographical feature sensor, a temperature sensor, a humidity sensor, amaturity sensor, and the like may be arranged in a vegetable farm, aking drone may flow above the farm, and network layer IP addresses maybe assigned to the group of sensor devices. Then, the king drone mayacquire sensor information from the group of sensor devices every timethe king drone flies over the area and may relay the sensor informationto a server on a cloud. Also, in regard to areas in which people gatherin limited periods, such as an event site or a swimming beach, a kingdrone may fly over the area, assign network layer IP addresses to LTEdevices in the area, and provide services in corporation withapplications on the terminals. The king drone may invalidate (that is,recover) the distributed network layer IP addresses after end of theperiod of the event and the like.

(6) Realization of in-Vehicle Sensor System

It is possible to collect sensor information acquired by various sensors(a road surface sensor, a radar, and the like) for monitoring the insideor the outside of a vehicle and to accumulate and analyze the sensorinformation in the vehicle by mounting the functions of the URN 2 on thevehicle. In addition, the URN 2 may be connected to the server on acloud as needed and perform more advanced analysis processing incorporation with big data and the like. It is possible to feed back theanalysis service to the vehicle, the URN 2, or the sensor even duringthe movement of the vehicle by realizing moving transmittivity of thevirtual cell.

(7) Realization of Long-Distance Wireless Connection Service

An increase in coverage is expected by realizing the virtual cells withthe nested structure and through so-called multiple-hop connection (thatis, connection of the virtual cells in series in a row), in which hopsof URN2-UE1 are connected in series in a row.

6. APPLICATION EXAMPLES

The technology of the present disclosure can be applied to variousproducts. For example, the P-GW 6 may be realized as a server of anytype such as a tower server, a rack server, a blade server, or the like.In addition, at least some of these constituent elements of the P-GW 6may be implemented by a control module mounted in a server (e.g., anintegrated circuit module configured in one die or a card or a bladeinserted into a slot of a blade server).

In addition, the UE 1 or the URN 2 may be realized as, for example, amobile terminal such as a smartphone, a tablet personal computer (PC), anotebook PC, a portable game terminal, a portable/dongle type mobilerouter, or a digital camera, or an in-vehicle terminal such as a carnavigation device. In addition, the UE 1 or the URN 2 may be realized asa terminal that performs machine-to-machine (M2M) communication (alsoreferred to as a machine type communication (MTC) terminal).Furthermore, at least some of these constituent elements of the UE 1 orthe URN 2 may be implemented by a module mounted in such a terminal (forexample, an integrated circuit module configured in one die).

6.1. Application Example with Regard to Communication Control Device

FIG. 46 is a block diagram illustrating an example of a schematicconfiguration of a server 700 to which the technology of the presentdisclosure may be applied. The server 700 includes a processor 701, amemory 702, a storage 703, a network interface 704, and a bus 706.

The processor 701 may be, for example, a central processing unit (CPU)or a digital signal processor (DSP) and controls various functions ofthe server 700. The memory 702 includes a random access memory (RAM) anda read only memory (ROM) and stores programs executed by the processor701 and data. The storage 703 can include a storage medium such as asemiconductor memory or a hard disk.

The network interface 704 is a wired communication interface forconnecting the server 700 to a wired communication network 705. Thewired communication network 705 may be a core network such as an evolvedpacket core (EPC) or a packet data network (PDN) such as the Internet.

The bus 706 connects the processor 701, the memory 702, the storage 703,and the network interface 704 to each other. The bus 706 may include twoor more buses that operate at different speeds (e.g., a high-speed busand a low-speed bus).

In the server 700 illustrated in FIG. 46, one or more constituentelements included in the P-GW 6 described with reference to FIG. 11 (thecommunication control unit 631) may be implemented by the processor 701.As an example, a program for causing a processor to function as the oneor more constituent elements (i.e., a program for causing a processor toexecute operations of the one or more constituent elements) may beinstalled in the server 700 and the processor 701 may execute theprogram. As another example, a module including the processor 701 andthe memory 702 may be mounted in the server 700 and the one or moreconstituent elements may be implemented by the module. In this case, themodule may store a program for causing a processor to function as theone or more constituent elements in the memory 702 and the program maybe executed by the processor 701. The server 700 or the module may beprovided as devices having the above-described one or more constituentelements as described above, or the program for causing a processor tofunction as the one or more constituent elements may be provided. Inaddition, a readable recording medium in which the program is recordedmay be provided.

In addition, in the server 700 shown in FIG. 46, the networkcommunication unit 610 described, for example, with reference to FIG. 11may be implemented by the network interface 704. Moreover, the storageunit 620 may be implemented by the memory 702 and/or the storage 703.

6.2. Application Example with Regard to Terminal Device and Relay DeviceFirst Application Example

FIG. 47 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 to which the technology of the presentdisclosure may be applied. The smartphone 900 includes a processor 901,a memory 902, a storage 903, an external connection interface 904, acamera 906, a sensor 907, a microphone 908, an input device 909, adisplay device 910, a speaker 911, a wireless communication interface912, one or more antenna switches 915, one or more antennas 916, a bus917, a battery 918, and an auxiliary controller 919.

The processor 901 may be, for example, a CPU or a system on a chip(SoC), and controls functions of an application layer and another layerof the smartphone 900. The memory 902 includes RAM and ROM, and stores aprogram that is executed by the processor 901, and data. The storage 903may include a storage medium such as a semiconductor memory and a harddisk. The external connection interface 904 is an interface forconnecting an external device such as a memory card and a universalserial bus (USB) device to the smartphone 900.

The camera 906 includes an image sensor such as a charge coupled device(CCD) and a complementary metal oxide semiconductor (CMOS), andgenerates a captured image. The sensor 907 may include a group ofsensors such as a measurement sensor, a gyro sensor, a geomagneticsensor, and an acceleration sensor. The microphone 908 converts soundsthat are input to the smartphone 900 to audio signals. The input device909 includes, for example, a touch sensor configured to detect touchonto a screen of the display device 910, a keypad, a keyboard, a button,or a switch, and receives an operation or an information input from auser. The display device 910 includes a screen such as a liquid crystaldisplay (LCD) and an organic light-emitting diode (OLED) display, anddisplays an output image of the smartphone 900. The speaker 911 convertsaudio signals that are output from the smartphone 900 to sounds.

The wireless communication interface 912 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 912 may typicallyinclude, for example, a BB processor 913 and an RF circuit 914. The BBprocessor 913 may perform, for example, encoding/decoding,modulating/demodulating, and multiplexing/demultiplexing, and performsvarious types of signal processing for wireless communication.Meanwhile, the RF circuit 914 may include, for example, a mixer, afilter, and an amplifier, and transmits and receives radio signals viathe antenna 916. The wireless communication interface 912 may also be aone chip module that has the BB processor 913 and the RF circuit 914integrated thereon. The wireless communication interface 912 may includethe multiple BB processors 913 and the multiple RF circuits 914, asillustrated in FIG. 47. Although FIG. 47 illustrates the example inwhich the wireless communication interface 912 includes the multiple BBprocessors 913 and the multiple RF circuits 914, the wirelesscommunication interface 912 may also include a single BB processor 913or a single RF circuit 914.

Furthermore, in addition to a cellular communication scheme, thewireless communication interface 912 may support another type ofwireless communication scheme such as a short-distance wirelesscommunication scheme, a near field communication scheme, and a wirelesslocal area network (LAN) scheme. In that case, the wirelesscommunication interface 912 may include the BB processor 913 and the RFcircuit 914 for each wireless communication scheme.

Each of the antenna switches 915 switches connection destinations of theantennas 916 among multiple circuits (such as circuits for differentwireless communication schemes) included in the wireless communicationinterface 912.

Each of the antennas 916 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the wireless communication interface 912 to transmit andreceive radio signals. The smartphone 900 may include the multipleantennas 916, as illustrated in FIG. 47. Although FIG. 47 illustratesthe example in which the smartphone 900 includes the multiple antennas916, the smartphone 900 may also include a single antenna 916.

Furthermore, the smartphone 900 may include the antenna 916 for eachwireless communication scheme. In that case, the antenna switches 915may be omitted from the configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the wireless communication interface 912, and the auxiliarycontroller 919 to each other. The battery 918 supplies power to blocksof the smartphone 900 illustrated in FIG. 47 via feeder lines, which arepartially shown as dashed lines in the figure. The auxiliary controller919 operates a minimum necessary function of the smartphone 900, forexample, in a sleep mode.

In the smartphone 900 shown in FIG. 47, one or more constituent elementsincluded in the UE 1 (the communication control unit 141) described withreference to FIG. 9, or one or more constituent elements included in theURN 2 (the relay unit 241 and/or the communication control unit 243)described with reference to FIG. 10 may be implemented by the wirelesscommunication interface 912. Alternatively, at least some of theseconstituent elements may be implemented by the processor 901 or theauxiliary controller 919. As an example, a module which includes a part(for example, the BB processor 913) or all of the wireless communicationinterface 912, the processor 901 and/or the auxiliary controller 919 maybe mounted in the smartphone 900, and the one or more constituentelements may be implemented by the module. In this case, the module maystore a program for causing the processor to function as the one or moreconstituent elements (i.e., a program for causing the processor toexecute operations of the one or more constituent elements) and mayexecute the program. As another example, the program for causing theprocessor to function as the one or more constituent elements may beinstalled in the smartphone 900, and the wireless communicationinterface 912 (for example, the BB processor 913), the processor 901and/or the auxiliary controller 919 may execute the program. Asdescribed above, the smartphone 900 or the module may be provided as adevice which includes the one or more constituent elements, and theprogram for causing the processor to function as the one or moreconstituent elements may be provided. In addition, a readable recordingmedium in which the program is recorded may be provided.

In addition, in the smartphone 900 shown in FIG. 47, the wirelesscommunication unit 120 described with reference to FIG. 9, or thewireless communication unit 220 described with reference to FIG. 10, forexample, may be implemented by the wireless communication interface 912(for example, the RF circuit 914). Moreover, the antenna unit 110 or theantenna unit 210 may be implemented by the antenna 916. Moreover, thestorage unit 130 or the storage unit 230 may be implemented by thememory 902.

Second Application Example

FIG. 48 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device 920 to which the technology ofthe present disclosure may be applied. The car navigation device 920includes a processor 921, a memory 922, a global positioning system(GPS) module 924, a sensor 925, a data interface 926, a content player927, a storage medium interface 928, an input device 929, a displaydevice 930, a speaker 931, a wireless communication interface 933, oneor more antenna switches 936, one or more antennas 937, and a battery938.

The processor 921 may be, for example, a CPU or a SoC, and controls anavigation function and another function of the car navigation device920. The memory 922 includes RAM and ROM, and stores a program that isexecuted by the processor 921, and data.

The GPS module 924 uses GPS signals received from a GPS satellite tomeasure a position (such as latitude, longitude, and altitude) of thecar navigation device 920. The sensor 925 may include a group of sensorssuch as a gyro sensor, a geomagnetic sensor, and a barometric sensor.The data interface 926 is connected to, for example, an in-vehiclenetwork 941 via a terminal that is not shown, and acquires datagenerated by the vehicle, such as vehicle speed data.

The content player 927 reproduces content stored in a storage medium(such as a CD and a DVD) that is inserted into the storage mediuminterface 928. The input device 929 includes, for example, a touchsensor configured to detect touch onto a screen of the display device930, a button, or a switch, and receives an operation or an informationinput from a user. The display device 930 includes a screen such as aLCD or an OLED display, and displays an image of the navigation functionor content that is reproduced. The speaker 931 outputs sounds of thenavigation function or the content that is reproduced.

The wireless communication interface 933 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 933 may typicallyinclude, for example, a BB processor 934 and an RF circuit 935. The BBprocessor 934 may perform, for example, encoding/decoding,modulating/demodulating, and multiplexing/demultiplexing, and performsvarious types of signal processing for wireless communication.Meanwhile, the RF circuit 935 may include, for example, a mixer, afilter, and an amplifier, and transmits and receives radio signals viathe antenna 937. The wireless communication interface 933 may be a onechip module having the BB processor 934 and the RF circuit 935integrated thereon. The wireless communication interface 933 may includethe multiple BB processors 934 and the multiple RF circuits 935, asillustrated in FIG. 48. Although FIG. 48 illustrates the example inwhich the wireless communication interface 933 includes the multiple BBprocessors 934 and the multiple RF circuits 935, the wirelesscommunication interface 933 may also include a single BB processor 934or a single RF circuit 935.

Furthermore, in addition to a cellular communication scheme, thewireless communication interface 933 may support another type ofwireless communication scheme such as a short-distance wirelesscommunication scheme, a near field communication scheme, and a wirelessLAN scheme. In that case, the wireless communication interface 933 mayinclude the BB processor 934 and the RF circuit 935 for each wirelesscommunication scheme.

Each of the antenna switches 936 switches connection destinations of theantennas 937 among multiple circuits (such as circuits for differentwireless communication schemes) included in the wireless communicationinterface 933.

Each of the antennas 937 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the wireless communication interface 933 to transmit andreceive radio signals. The car navigation device 920 may include themultiple antennas 937, as illustrated in FIG. 48. Although FIG. 48illustrates the example in which the car navigation device 920 includesthe multiple antennas 937, the car navigation device 920 may alsoinclude a single antenna 937.

Furthermore, the car navigation device 920 may include the antenna 937for each wireless communication scheme. In that case, the antennaswitches 936 may be omitted from the configuration of the car navigationdevice 920.

The battery 938 supplies power to blocks of the car navigation device920 illustrated in FIG. 48 via feeder lines that are partially shown asdashed lines in the figure. The battery 938 accumulates power suppliedform the vehicle.

In the car navigation device 920 shown in FIG. 48, one or moreconstituent elements included in the UE 1 (the communication controlunit 141) described with reference to FIG. 9, or one or more constituentelements included in the URN 2 (the relay unit 241 and/or thecommunication control unit 243) described with reference to FIG. 10 maybe implemented by the wireless communication interface 933.Alternatively, at least some of these constituent elements may beimplemented by the processor 921. As an example, a module which includesa part (for example, the BB processor 934) or all of the wirelesscommunication interface 933 and/or the processor 921 may be mounted inthe car navigation device 920, and the one or more constituent elementsmay be implemented by the module. In this case, the module may store aprogram for causing the processor to function as the one or moreconstituent elements (i.e., a program for causing the processor toexecute operations of the one or more constituent elements) and mayexecute the program. As another example, the program for causing theprocessor to function as the one or more constituent elements may beinstalled in the car navigation device 920, and the wirelesscommunication interface 933 (for example, the BB processor 934) and/orthe processor 921 may execute the program. As described above, the carnavigation device 920 or the module may be provided as a device whichincludes the one or more constituent elements, and the program forcausing the processor to function as the one or more constituentelements may be provided. In addition, a readable recording medium inwhich the program is recorded may be provided.

In addition, in the car navigation device 920 shown in FIG. 48, thewireless communication unit 120 described with reference to FIG. 9, orthe wireless communication unit 220 described with reference to FIG. 10,for example, may be implemented by the wireless communication interface933 (for example, the RF circuit 935). Moreover, the antenna unit 110 orthe antenna unit 210 may be implemented by the antenna 937. Moreover,the storage unit 130 or the storage unit 230 may be implemented by thememory 922.

The technology of the present disclosure may also be realized as anin-vehicle system (or a vehicle) 940 including one or more blocks of thecar navigation device 920, the in-vehicle network 941, and a vehiclemodule 942. In other words, the in-vehicle system (or a vehicle) 940 maybe provided as a device which includes the communication control unit141, or the relay unit 241 and the communication control unit 243. Thevehicle module 942 generates vehicle data such as vehicle speed, enginespeed, and trouble information, and outputs the generated data to thein-vehicle network 941.

7. CONCLUSION

The embodiment of the present disclosure has been described above withreference to FIGS. 1 to 48. As described above, the URN 2 according tothe embodiment assigns the network layer IP address, which has a prefixportion that is at least partially common, to each of the one or moresecond devices while relaying the wireless signals between the firstdevice that is the connection destination and the one or moresubordinate second devices. In this manner, IP moving transmittivity inthe virtual cell is realized, and it becomes possible to suppress theamount of information to be stored in the P-GW 6, the S-GW 5, or theDeNB 3 for the URN 2 or the subordinate second devices.

The preferred embodiment of the present disclosure has been describedabove with reference to the accompanying drawings, whilst the presentdisclosure is not limited to the above examples. A person skilled in theart may find various alterations and modifications within the scope ofthe appended claims, and it should be understood that they willnaturally come under the technical scope of the present disclosure.

In addition, the processing described by using the flowcharts and thesequence diagrams in this specification may not be necessarily executedin the orders described in the drawings. Some processing steps may beexecuted in parallel. In addition, additional processing steps may beemployed, and a part of the processing steps may be omitted.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art from the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

A relay device including:

a relay unit that relays a wireless signal between a first device thatis a connection destination and one or more subordinate second devices;and

a control unit that assigns a network layer IP address, which has aprefix portion that is at least partially common, to each of the one ormore second devices.

(2)

The relay device according to (1), in which a transmission path setbetween the relay device and a packet data network gateway (P-GW) isdiverted for a section between the relay device and the P-GW in atransmission path set between the second devices and the P-GW.

(3)

The relay device according to (2), in which the transmission path is abearer.

(4)

The relay device according to (2) or (3), in which the transmission pathis an IP flow.

(5)

The relay device according to any one of (1) to (4), in which thecontrol unit notifies the second devices of information indicating thatthe relay device is to start handover.

(6)

The relay device according to (5), in which the control unit notifiesthe second devices of information indicating that the relay device hascompleted the handover.

(7)

The relay device according to any one of (1) to (6), in which eachvirtual cell formed by the relay device or another relay device isidentified by a non-common portion of the prefix portion.

(8)

The relay device according to any one of (1) to (7), in which the prefixportion is a subnet prefix in IPv6.

(9)

The relay device according to any one of (1) to (8), in which thecontrol unit assigns the network layer IP address to the relay device.

(10)

A terminal device including:

a processing unit that performs communication with a relay device byusing a first network layer IP address, which is assigned to one or moreterminal devices connected to the same relay device, and has a prefixportion that is at least partially common.

(11)

The terminal device according to (10), in which the processing unitsuppresses a procedure for attachment to another network for apredetermined period of time after the relay device starts handover.

(12)

The terminal device according to (10) or (11), further including:

a storage unit that stores a clock time at which a procedure forattachment to the relay device has been completed.

(13)

The terminal device according to (12), in which the processing unit usesthe first network layer IP address for a socket that is opened after theclock time at which the procedure for attachment to the relay device hasbeen completed and continuously uses a second network layer IP addressassigned before the handover for a socket that is opened before theclock time at which the procedure for attachment to the relay device hasbeen completed.

(14)

The terminal device according to (13), in which the processing unitnotifies the relay device of information indicating that the socket, forwhich the second network layer IP address has been used, has beenclosed.

(15)

A communication control device including:

a processing unit that notifies a relay device that relays a wirelesssignal between a first device that is a connection destination and oneor more subordinate second devices and assigns a network layer IPaddress, which has a prefix portion that is at least partially common,to each of the one or more second devices of the common portion of theprefix portion.

(16)

The communication control device according to (15), further including:

a storage unit that stores the prefix portion in association with therelay device.

(17)

The communication control device according to (15) or (16), in which theprocessing unit notifies a device that relays communication between therelay device and the communication control device of information forassociating the prefix portion with the relay device.

(18)

A method including:

relaying a wireless signal between a first device that is a connectiondestination and one or more subordinate second devices; and

a control unit that assigns a network layer IP address, which has aprefix portion that is at least partially common, to each of the one ormore second devices by a processor.

(19)

A method including:

performing, by a processor, communication with a relay device by using afirst network layer IP address, which is assigned to one or moreterminal devices connected to the same relay device, and has a prefixportion that is at least partially common.

(20)

A method including:

notifying, by a processor, a relay device that relays a wireless signalbetween a first device that is a connection destination and one or moresubordinate second devices and assigns a network layer IP address, whichhas a prefix portion that is at least partially common, to each of theone or more second devices of the common portion of the prefix portion.

REFERENCE SIGNS LIST

-   1 UE-   2 URN-   3 DeNB-   4 eNB-   5 S-GW-   6 P-GW-   7 MME-   8 HSS-   9 PCRF-   10 PDN-   110 antenna unit-   120 wireless communication unit-   130 storage unit-   140 processing unit-   141 communication control unit-   210 antenna unit-   220 wireless communication unit-   230 storage unit-   240 processing unit-   241 relay unit-   243 communication control unit-   610 network communication unit-   620 storage unit-   630 processing unit-   631 communication control unit

The invention claimed is:
 1. A terminal device comprising: a processingunit that performs communication with a relay device by using a firstnetwork layer IP address, which is assigned to one or more terminaldevices connected to the same relay device, and has a prefix portionthat is at least partially common; and a storage unit that stores aclock time at which a procedure for attachment to the relay device hasbeen completed, wherein the processing unit uses the first network layerIP address for a socket that is opened after the clock time at which theprocedure for attachment to the relay device has been completed andcontinuously uses a second network layer IP address assigned before thehandover for a socket that is opened before the clock time at which theprocedure for attachment to the relay device has been completed.
 2. Theterminal device according to claim 1, wherein the processing unitsuppresses a procedure for attachment to another network for apredetermined period of time after the relay device starts handover. 3.The terminal device according to claim 1, wherein the processing unitnotifies the relay device of information indicating that the socket, forwhich the second network layer IP address has been used, has beenclosed.
 4. A communication control device comprising: a processing unitthat notifies a relay device that relays a wireless signal between afirst device that is a connection destination and one or moresubordinate second devices and assigns a first network layer IP address,which has a prefix portion that is at least partially common, to each ofthe one or more second devices of the common portion of the prefixportion; and a storage unit that stores a clock time at which aprocedure for attachment to the relay device has been completed, whereinthe processing unit uses the first network layer IP address for a socketthat is opened after the clock time at which the procedure forattachment to the relay device has been completed and continuously usesa second network layer IP address assigned before the handover for asocket that is opened before the clock time at which the procedure forattachment to the relay device has been completed.
 5. The communicationcontrol device according to claim 4, wherein the processing unitnotifies a device that relays communication between the relay device andthe communication control device of information for associating theprefix portion with the relay device.
 6. A method comprising: relaying awireless signal between a first device that is a connection destinationand one or more subordinate second devices; and assigning a networklayer IP address, which has a prefix portion that is at least partiallycommon, to each of the one or more second devices by a processor,storing a clock time at which a procedure for attachment to a relaydevice has been completed, using the first network layer IP address fora socket that is opened after the clock time at which the procedure forattachment to the relay device has been completed, and continuouslyusing a second network layer IP address assigned before the handover fora socket that is opened before the clock time at which the procedure forattachment to the relay device has been completed.
 7. A terminal devicecomprising: circuitry configured to communicate with a relay device byusing a first network layer IP address, which is assigned to one or moreterminal devices connected to the same relay device, and has a prefixportion that is at least partially common; and store a clock time atwhich a procedure for attachment to the relay device has been completed,use the first network layer IP address for a socket that is opened afterthe clock time at which the procedure for attachment to the relay devicehas been completed and continuously use a second network layer IPaddress assigned before the handover for a socket that is opened beforethe clock time at which the procedure for attachment to the relay devicehas been completed.